diff --git a/src/Model/Contact.php b/src/Model/Contact.php
index e790fd4843..d7f27ddd55 100644
--- a/src/Model/Contact.php
+++ b/src/Model/Contact.php
@@ -27,6 +27,66 @@ require_once 'include/text.php';
  */
 class Contact extends BaseObject
 {
+	/**
+	 * @brief Returns a list of contacts belonging in a group
+	 *
+	 * @param int $gid
+	 * @return array
+	 */
+	public static function getByGroupId($gid)
+	{
+		$return = [];
+		if (intval($gid)) {
+			$stmt = dba::p('SELECT `group_member`.`contact-id`, `contact`.*
+				FROM `contact`
+				INNER JOIN `group_member`
+					ON `contact`.`id` = `group_member`.`contact-id`
+				WHERE `gid` = ?
+				AND `group_member`.`uid` = ?
+				AND NOT `contact`.`self`
+				AND NOT `contact`.`blocked`
+				AND NOT `contact`.`pending`
+				ORDER BY `contact`.`name` ASC',
+				$gid,
+				local_user()
+			);
+			if (DBM::is_result($stmt)) {
+				$return = dba::inArray($stmt);
+			}
+		}
+
+		return $return;
+	}
+
+	/**
+	 * @brief Returns the count of OStatus contacts in a group
+	 *
+	 * @param int $gid
+	 * @return int
+	 */
+	public static function getOStatusCountByGroupId($gid)
+	{
+		$return = 0;
+		if (intval($gid)) {
+			$contacts = dba::fetch_first('SELECT COUNT(*) AS `count`
+				FROM `contact`
+				INNER JOIN `group_member`
+					ON `contact`.`id` = `group_member`.`contact-id`
+				WHERE `gid` = ?
+				AND `group_member`.`uid` = ?
+				AND `contact`.`network` = ?
+				AND `contact`.`notify` != ""',
+				$gid,
+				local_user(),
+				NETWORK_OSTATUS
+			);
+			$return = $contacts['count'];
+		}
+
+		return $return;
+	}
+
+
 	/**
 	 * Creates the self-contact for the provided user id
 	 *
diff --git a/src/Model/Group.php b/src/Model/Group.php
new file mode 100644
index 0000000000..51b709f536
--- /dev/null
+++ b/src/Model/Group.php
@@ -0,0 +1,430 @@
+<?php
+
+/**
+ * @file src/Model/Group.php
+ */
+
+namespace Friendica\Model;
+
+use Friendica\BaseObject;
+use Friendica\Database\DBM;
+use dba;
+
+require_once 'boot.php';
+require_once 'include/text.php';
+
+/**
+ * @brief functions for interacting with the group database table
+ */
+class Group extends BaseObject
+{
+	/**
+	 * @brief Create a new contact group
+	 *
+	 * Note: If we found a deleted group with the same name, we restore it
+	 *
+	 * @param int $uid
+	 * @param string $name
+	 * @return boolean
+	 */
+	public static function create($uid, $name)
+	{
+		$return = false;
+		if (x($uid) && x($name)) {
+			$gid = self::getIdByName($uid, $name); // check for dupes
+			if ($gid !== false) {
+				// This could be a problem.
+				// Let's assume we've just created a group which we once deleted
+				// all the old members are gone, but the group remains so we don't break any security
+				// access lists. What we're doing here is reviving the dead group, but old content which
+				// was restricted to this group may now be seen by the new group members.
+				$group = dba::select('group', ['deleted'], ['id' => $gid], ['limit' => 1]);
+				if (DBM::is_result($group) && $group['deleted']) {
+					dba::update('group', ['deleted' => 0], ['gid' => $gid]);
+					notice(t('A deleted group with this name was revived. Existing item permissions <strong>may</strong> apply to this group and any future members. If this is not what you intended, please create another group with a different name.') . EOL);
+				}
+				return true;
+			}
+
+			$return = dba::insert('group', ['uid' => $uid, 'name' => $name]);
+		}
+		return $return;
+	}
+
+	/**
+	 * @brief Get a list of group ids a contact belongs to
+	 *
+	 * @todo Get rid of $uid, the contact id already bears the information
+	 *
+	 * @param int $uid
+	 * @param int $cid
+	 * @return array
+	 */
+	private static function getByContactIdForUserId($uid, $cid)
+	{
+		$stmt = dba::p('SELECT `id`
+			FROM `group`
+			INNER JOIN `group_member`
+				ON `group_member`.`gid` = `group`.`id`
+			WHERE `group`.`uid` = ?
+			AND `group_member`.`contact-id` = ?',
+			$uid,
+			$cid
+		);
+
+		$return = [];
+		if (DBM::is_result($stmt)) {
+			while($group = dba::fetch($stmt)) {
+				$return[] = $group['id'];
+			}
+		}
+
+		return $return;
+	}
+
+	/**
+	 * @brief count unread group items
+	 *
+	 * Count unread items of each groups of the local user
+	 *
+	 * @return array
+	 * 	'id' => group id
+	 * 	'name' => group name
+	 * 	'count' => counted unseen group items
+	 */
+	public static function countUnseen()
+	{
+		$stmt = dba::p("SELECT `group`.`id`, `group`.`name`,
+				(SELECT COUNT(*) FROM `item` FORCE INDEX (`uid_unseen_contactid`)
+					WHERE `uid` = ?
+					AND `unseen`
+					AND `contact-id` IN
+						(SELECT `contact-id`
+						FROM `group_member`
+						WHERE `group_member`.`gid` = `group`.`id`
+						AND `group_member`.`uid` = ?)
+					) AS `count`
+				FROM `group`
+				WHERE `group`.`uid` = ?;",
+			local_user(),
+			local_user(),
+			local_user()
+		);
+
+		return dba::inArray($stmt);
+	}
+
+	/**
+	 * @brief Get the group id for a user/name couple
+	 *
+	 * Returns false if no group has been found.
+	 *
+	 * @param int $uid
+	 * @param string $name
+	 * @return int|boolean
+	 */
+	public static function getIdByName($uid, $name)
+	{
+		if ((! $uid) || (! strlen($name))) {
+			return false;
+		}
+
+		$group = dba::select('group', ['id'], ['uid' => $uid, 'name' => $name], ['limit' => 1]);
+		if (DBM::is_result($group)) {
+			return $group['id'];
+		}
+
+		return false;
+	}
+
+	/**
+	 * @brief Mark a group as deleted
+	 *
+	 * @param type $gid
+	 * @return boolean
+	 */
+	public static function remove($gid) {
+		if (! $gid) {
+			return false;
+		}
+
+		// remove group from default posting lists
+		$user = dba::select('user', ['def_gid', 'allow_gid', 'deny_gid'], ['uid' => $uid], ['limit' => 1]);
+		if (DBM::is_result($user)) {
+			$change = false;
+
+			if ($user['def_gid'] == $gid) {
+				$user['def_gid'] = 0;
+				$change = true;
+			}
+			if (strpos($user['allow_gid'], '<' . $gid . '>') !== false) {
+				$user['allow_gid'] = str_replace('<' . $gid . '>', '', $user['allow_gid']);
+				$change = true;
+			}
+			if (strpos($user['deny_gid'], '<' . $gid . '>') !== false) {
+				$user['deny_gid'] = str_replace('<' . $gid . '>', '', $user['deny_gid']);
+				$change = true;
+			}
+
+			if ($change) {
+				dba::update('user', $user, ['uid' => $uid]);
+			}
+		}
+
+		// remove all members
+		dba::delete('group_member', ['gid' => $gid]);
+
+		// remove group
+		$return = dba::update('group', ['deleted' => 1], ['id' => $gid]);
+
+		return $return;
+	}
+
+	/**
+	 * @brief Mark a group as deleted based on its name
+	 *
+	 * @deprecated Use Group::remove instead
+	 *
+	 * @param type $uid
+	 * @param type $name
+	 * @return type
+	 */
+	public static function removeByName($uid, $name) {
+		$return = false;
+		if (x($uid) && x($name)) {
+			$gid = self::getIdByName($uid, $name);
+
+			$return = self::remove($gid);
+		}
+
+		return $return;
+	}
+
+	/**
+	 * @brief Adds a contact to a group
+	 *
+	 * @param int $gid
+	 * @param int $cid
+	 * @return boolean
+	 */
+	public static function addMember($gid, $cid)
+	{
+		if (!($gid && $cid)) {
+			return false;
+		}
+
+		$row_exists = dba::exists('group_member', ['gid' => $gid, 'contact-id' => $cid]);
+		if ($row_exists) {
+			// Row already existing, nothing to do
+			$return = true;
+		} else {
+			$return = dba::insert('group_member', ['gid' => $gid, 'contact-id' => $cid]);
+		}
+
+		return $return;
+	}
+
+	/**
+	 * @brief Removes a contact from a group
+	 *
+	 * @param int $gid
+	 * @param int $cid
+	 * @return boolean
+	 */
+	public static function removeMember($gid, $cid)
+	{
+		if (!$gid) {
+			return false;
+		}
+
+		if (!($gid && $cid)) {
+			return false;
+		}
+
+		$return = dba::delete('group_member', ['gid' => $gid, 'contact-id' => $cid]);
+
+		return $return;
+	}
+
+	/**
+	 * @brief Removes a contact from a group based on its name
+	 *
+	 * @deprecated Use Group::removeMember instead
+	 *
+	 * @param int $uid
+	 * @param string $name
+	 * @param int $cid
+	 * @return boolean
+	 */
+	public static function removeMemberByName($uid, $name, $cid)
+	{
+		$gid = self::getIdByName($uid, $name);
+
+		$return = self::removeMember($gid, $cid);
+
+		return $return;
+	}
+
+	/**
+	 * @brief Returns the combined list of contact ids from a group id list
+	 *
+	 * @param array $group_ids
+	 * @param boolean $check_dead
+	 * @param boolean $use_gcontact
+	 * @return array
+	 */
+	public static function expand($group_ids, $check_dead = false, $use_gcontact = false)
+	{
+		if (!(is_array($group_ids) && count($group_ids))) {
+			return [];
+		}
+
+		$condition = '`gid` IN (' . substr(str_repeat("?, ", count($group_ids)), 0, -2) . ')';
+		if ($use_gcontact) {
+			$sql = 'SELECT `gcontact`.`id` AS `contact-id` FROM `group_member`
+					INNER JOIN `contact` ON `contact`.`id` = `group_member`.`contact-id`
+					INNER JOIN `gcontact` ON `gcontact`.`nurl` = `contact`.`nurl`
+				WHERE ' . $condition;
+			$param_arr = array_merge([$sql], $group_ids);
+			$stmt = call_user_func_array('dba::p', $param_arr);
+		} else {
+			$condition_array = array_merge([$condition], $group_ids);
+			$stmt = dba::select('group_member', ['contact-id'], $condition_array);
+		}
+
+		$return = array();
+		if (DBM::is_result($stmt)) {
+			while($group_member = dba::fetch($stmt)) {
+				$return[] = $group_member['contact-id'];
+			}
+		}
+
+		if ($check_dead && !$use_gcontact) {
+			require_once 'include/acl_selectors.php';
+			$return = prune_deadguys($return);
+		}
+		return $return;
+	}
+
+	/**
+	 * @brief Returns a templated group selection list
+	 *
+	 * @param int $uid
+	 * @param int $gid An optional pre-selected group
+	 * @param string $label An optional label of the list
+	 * @return string
+	 */
+	public static function displayGroupSelection($uid, $gid = 0, $label = '')
+	{
+		$o = '';
+
+		$groups = dba::select('group', [], ['deleted' => 0, 'uid' => $uid], ['order' => ['name' => 'ASC']]);
+
+		$display_groups = [
+			[
+				'name' => '',
+				'id' => '0',
+				'selected' => ''
+			]
+		];
+		foreach ($groups as $group) {
+			$display_groups[] = [
+				'name' => $group['name'],
+				'id' => $group['id'],
+				'selected' => $gid == $group['id'] ? 'true' : ''
+			];
+		}
+		logger('groups: ' . print_r($display_groups, true));
+
+		if ($label == '') {
+			$label = t('Default privacy group for new contacts');
+		}
+
+		$o = replace_macros(get_markup_template('group_selection.tpl'), array(
+			'$label' => $label,
+			'$groups' => $display_groups
+		));
+		return $o;
+	}
+
+	/**
+	 * @brief Create group sidebar widget
+	 *
+	 * @param string $every
+	 * @param string $each
+	 * @param string $editmode
+	 * 	'standard' => include link 'Edit groups'
+	 * 	'extended' => include link 'Create new group'
+	 * 	'full' => include link 'Create new group' and provide for each group a link to edit this group
+	 * @param int $group_id
+	 * @param int $cid
+	 * @return string
+	 */
+	public static function sidebarWidget($every = 'contacts', $each = 'group', $editmode = 'standard', $group_id = 0, $cid = 0)
+	{
+		$o = '';
+
+		if (!local_user()) {
+			return '';
+		}
+
+		$display_groups = [
+			[
+				'text' => t('Everybody'),
+				'id' => 0,
+				'selected' => (($group_id == 0) ? 'group-selected' : ''),
+				'href' => $every,
+			]
+		];
+
+		$groups = dba::select('group', [], ['deleted' => 0, 'uid' => local_user()], ['order' => ['name' => 'ASC']]);
+
+		$member_of = array();
+		if ($cid) {
+			$member_of = self::getByContactIdForUserId(local_user(), $cid);
+		}
+
+		if (DBM::is_result($groups)) {
+			foreach ($groups as $group) {
+				$selected = (($group_id == $group['id']) ? ' group-selected' : '');
+
+				if ($editmode == 'full') {
+					$groupedit = [
+						'href' => 'group/' . $group['id'],
+						'title' => t('edit'),
+					];
+				} else {
+					$groupedit = null;
+				}
+
+				$display_groups[] = [
+					'id'   => $group['id'],
+					'cid'  => $cid,
+					'text' => $group['name'],
+					'href' => $each . '/' . $group['id'],
+					'edit' => $groupedit,
+					'selected' => $selected,
+					'ismember' => in_array($group['id'], $member_of),
+				];
+			}
+		}
+
+		$tpl = get_markup_template('group_side.tpl');
+		$o = replace_macros($tpl, [
+			'$add' => t('add'),
+			'$title' => t('Groups'),
+			'$groups' => $display_groups,
+			'newgroup' => $editmode == 'extended' || $editmode == 'full' ? 1 : '',
+			'grouppage' => 'group/',
+			'$edittext' => t('Edit group'),
+			'$ungrouped' => $every === 'contacts' ? t('Contacts not in any group') : '',
+			'$createtext' => t('Create a new group'),
+			'$creategroup' => t('Group Name: '),
+			'$editgroupstext' => t('Edit groups'),
+			'$form_security_token' => get_form_security_token('group_edit'),
+		]);
+
+
+		return $o;
+	}
+}
diff --git a/src/Model/User.php b/src/Model/User.php
index 54d2d3bc60..a66075cac6 100644
--- a/src/Model/User.php
+++ b/src/Model/User.php
@@ -8,10 +8,12 @@
 namespace Friendica\Model;
 
 use Friendica\Core\Config;
+use Friendica\Core\PConfig;
 use Friendica\Core\System;
 use Friendica\Core\Worker;
 use Friendica\Database\DBM;
 use Friendica\Model\Contact;
+use Friendica\Model\Group;
 use Friendica\Model\Photo;
 use Friendica\Object\Image;
 use dba;
@@ -30,6 +32,36 @@ require_once 'include/text.php';
  */
 class User
 {
+	/**
+	 * @brief Returns the default group for a given user and network
+	 *
+	 * @param int $uid User id
+	 * @param string $network network name
+	 *
+	 * @return int group id
+	 */
+	public static function getDefaultGroup($uid, $network = '')
+	{
+		$default_group = 0;
+
+		if ($network == NETWORK_OSTATUS) {
+			$default_group = PConfig::get($uid, "ostatus", "default_group");
+		}
+
+		if ($default_group != 0) {
+			return $default_group;
+		}
+
+		$user = dba::select('user', ['def_gid'], ['uid' => $uid], ['limit' => 1]);
+
+		if (DBM::is_result($user)) {
+			$default_group = $user["def_gid"];
+		}
+
+		return $default_group;
+	}
+
+
 	/**
 	 * @brief Authenticate a user with a clear text password
 	 *