Find, read & explore some wikis
Marketing: http://www.stephanspencer.com/wikis/wikis-for-marketing
Educational: http://wikisineducation.wetpaint.com/page/How+we+use+wikis+in+class?t=anon
List of wikis: http://en.wikipedia.org/wiki/List_of_wikis

Businesses & wikis
How To Use Wikis For Business
Wikis Are Now Serious Business
Would Your Business Benefit from a Wiki?

Wiki:
Comment on the wiki’s you’ve looked at
What do you dis/like about the use of wikis?
Would you ever use/create one?
How are wikis good for businesses?

Twitter:
Comment on how tweeting is going for you, any interesting things you’ve come across, and the tweets you are reading. Find a way to tweet that works for you – check out these suggestions:
Top ten types of Tweets
Six Types of Tweets
Get Twhirl and try using that interface to tweet instead.

Experiment with #Hashtags at http://hashtags.org
Find something you’re interested in and see what’s being tweeted about it.