Last year we closely examined some of IBM's social technology work, they link it to their large workforce very successfully.
They have released a beta that includes many of the tools useful for working together in teams, including " ... a social network, a document sharing tool which includes tagging for quick access, a task management solution, a forms wizard, a charting tool and a chat application ... ". And most fundamentally, screen sharing. This is still under their Lotus URL, but does not require Lotus Notes.
I have done some examining of information sharing capabilities for remote meetings, and most are either too expensive or problematic. I also like their notion of an 'extended meeting'. They have several short videos that explain this. Free cloud signup here, still exploring.
Update: For any of you intending to explore this, I discovered later that this is not a completely free and open beta. You can sign up, but later found the signup is an application and by some unclear criteria you will be accepted or not. Still trying to get access to do an evaluation.
Update2: Now up and running on the Beta. If anyone out there would like to co-evaluate this (it is a collaboration venue) let me know. I will publish my findings in the upcoming weeks.