Google properties:

• Google Talk status updates
• Google Reader shared items
• Google Calendar events (added, invited, updated?)
• Google Documents (recent changes, new, updated)
• Picasa (new photos from friends)
• Google Video / YouTube (new videos from friends)
• Blogger posts
• Orkut updates (whatever those consist of)
• Gadgets added to home page, aka “iGoogle”
• Google Shared Stuff (or whatever it’s called) added

External properties:

• Anything with an RSS feed basically… including stuff like…
• Twitter/Pownce/Jaiku, Tumblr
• Blogs not on Blogger (like: Facebook Notes, LiveJournal, VOX, Xanga, Windows Live Spaces, WordPress)
• Photos not on Picasa (aka Flickr, Webshots, Smugmug)
• Bookmarked items not on Google Shared Stuff (aka del.icio.us, ma.gnol.ia, etc.)
• Last.fm, Pandora (any other social music with RSS feeds?)
• Digg posts, votes feeds
• Upcoming (Yahoo Events)
• Apps built on social APIs (think Werewolves and Vampires), though these may come in the form of Gadgets

What I’m wondering – well there’s several things, but I think the highest on my list of wondering – is where the Activity Stream will be displayed. An answer to that may solve the second thing on my list, which is, how is Google going to decide who my friends are and which updates I want to see on the Activity Stream?

They have the new contact manager that they’re rolling out with the update to Gmail, but I have 220 Gmail contacts, and I certainly don’t want to see all their updates from all their Google (and other) activities… And I’m guessing most of them don’t want me to see all that stuff either. So… Google will have to do two things (most likely): 1) Have some way of determining who is allowed to see what (privacy level settings), and 2) create an algorithm like Facebook to decide what is most important to show.

I don’t like Facebook’s algorithm, but I feel like Google could come up with a much better one. I also think, though, that Google could create an interface (like the one on Socialstream) that would allow for a much larger number of items to be displayed and still make it fairly easy for users to understand.

I’m waiting for the November 8th (or so) announcement, but I’m pretty sure it will be a release of the API glue, which will seem underwhelming until Google (or developers) starting using the glue to stick things together.