Collaboration: First, look at collaboration using docs at www.google.com. You will get an invitation to go in and do an evaluation there. This would be a great way to work out text with a client etc.
Next I want you to look at wikis. An example is www.wikispaces.com. A site I used at one time is http://cis44.wikispaces.com/.
Some information is http://wikihosting.net/
Then you should also look at PageFlakes. I have an example on the first page of my website under the name of Tech News. I have a series of RSS feeds coming to the page to keep me up on tech news in one space.
Some information about using blogs:
http://www.problogger.net/archives/2006/02/15/choosing-a-blog-platform/
http://www.lonelymarketer.com/2007/09/05/beginners-guide-to-setting-up-a-first-blog-site/
http://www.problogger.net/archives/2006/01/18/blog-platforms-poll-results/
http://www.ojr.org/ojr/images/blog_software_comparison.cfm
http://www.ojr.org/ojr/stories/050714gardner/
http://www.microsoft.com/windowsxp/using/windowsmessenger/northrup_msnblogs.mspx