Gmail, reader and docs are not open source. they, like most other webapps, are on the internet to make money, directly(selling to businesses) and indirectly(advertising). Google does give a lot to open source though, just not the things you mentioned.

Also, google wave is not simply a collaborative program.
I use google docs for collaborative document editing, and haven’t yet found a use for google wave. It’s something of a cross between collab editing, emailing, and IM. Google say they made it to change the way we communicate online, and that may be why I don’t use it.

At least that\’s what you get when you go to http://www.EtherPad.com