To leave a group you're a member of, go to that group's page and click the "More" button at the top, near the group's avatar. Select "Leave group" from the dropdown that opens, and confirm that you want to leave the group.
If you have a group you don't want to be leader of any more, you can pass the leadership on to another group member. To do this, go to that group's page and select "Abdicate" from the "More" button dropdown at the top, near the group's avatar.
On the following page, enter the username of the group member you want to become leader, and click the "Do it" button. That user will then receive a message asking if they want to become leader of your group, or not. If they accept, they'll gain leadership of your group (but if the decline, you'll have to stay around as leader a bit longer!).
When you create a group, you have the option of making it open for everyone to join ("Open") or making it exclusive, which means that all new members will have to be accepted by either you, the group leader ("Owner Approval"), or other group members ("Member Approval").
You can change these settings any time under "Edit Details", which you can select from the "More" button on your group's page. If you set your group to "Closed", no one will be able to join it any more.
Furthermore, you can control who can view and post in your group's forum and leave messages in your group's shoutbox, by choosing the respective setting under "Group Forum/Shoutbox Access" on the "Edit Details" page.
Once a group has a few members, it’ll start to have charts generated: Overall charts, and charts which are unique to it.
The way that overall charts work is that every “1” will represent a group member. For example, say there are 3 people in a group who listened to a certain artist in the last week, it’ll say “3” in the charts and this will mean that 3 members listened to that artist, and not the number of times that the artist was played by all group members.
The “unique to this group” charts which you can choose to view on a group’s page emphasise what is unique about the music taste of that group's members, compared to the listening habits of all other Last.fm users.
This means that these charts don’t just show you what a group’s members listen to like the overall group charts do, but what is special about their listening habits in comparison to what other users on Last.fm listen to (considering the average listener’s behaviour):
For example if the members of a group listen to artist A much more often than others do, artist A will be more unique to their group as this will be special to their listening habits, compared to everyone else’s; if they listen to Artist B, but everyone else also listens to artist B a lot, then this will be less special and artist B will be less unique to their group.
You can do this from your profile by clicking 'journal' and then 'write a new journal entry'. Once you have created your journal, tick the option at the bottom 'submit this entry to one or more groups'. You will then see a list of all the groups you belong to and you can select the group(s) you would like to post your article to. The journal will then automatically appear on the chosen group page (however, note that sometimes group leaders don't allow direct submissions or have to accept your submitted journal entry first).
No, it's not possible to delete groups. This is to prevent abuse.
However, our system automatically deletes groups once they're older than at least three months and have less than three members. The easiest way to delete a group you lead is to remove any other members, close the group by setting its "Join Status" to "Closed", and then remove yourself.