indeed this is a very interesting topic. Some academic research is ongoing on this matter, especially on the European level (and maybe other but I am not award of that). There is a EC Coordination Action which deal with presence which is called PEACH:

http://www.peachbit.org/

I don’t know their involvement with Free Software but I know the coordinators of this project (I have organized a workshop with them). Drop me an email if you want to be put in contact with them.

Syncing pictures is important to people who meet a lot of people all the time (what MS calls “Corridor Warriors” or “Meeting Weenies”).

http://www.nuxified.org/blog/ubuntu_down_the_drain

I mean mainly the free/non-free aspect, also the unstability of edgy … or maybe you’ve done so already elsewhere, in that case I am sorry, and could you direct me to the correct place?

Maybe a smart algorithm that uses time of day in addition to time since last keyboard or mouse event to determine if I am available. A smart one that says that I am available never available when I am using openoffice.org writer but may be available when using firefox would be nice.

Just think of Gmail with its Google Talk and email integration. While viewing an email conversation, you can see a little green dot next to one of the replies, which means the user that sent that particular reply is online. By clicking “Reply to Chat”, you can send an IM in reply to the message, and have it still appear in the context of the email conversation view when it is searched.