Blogs

Here's a great introduction to blogs: Blogging 101. And here's an in-depth definition from Wikipedia: Weblogs. And here are some examples from PP affiliates who have used blogs to promote and document their lobby days: lobby day ideas.

Here is a brief summary of some of the leading blogging tools:

Blogger
pros: free, hosted on their server, easy to use, built-in templates
cons: limited functions, address is ___.blogspot.com, doesn't handle comments well

TypePad
pros: hosted on their server, comments, image galleries (for extra $3/month), easy to use, built-in templates
cons: costs $5/month, limited functions

WordPress
pros: free, better archiving, flexible design & structure, comment moderation, unlimited authors and guest writers, free plug-ins, open source (good politics)
cons: host on your own server (or at dreamhost.com for about $10/month)
neutral: use your own wrapper (w/ some light programming)

MovableType
pros: limited free version, better archiving, flexible design & structure, comment moderation, free plug-ins
cons: have to pay for support, host on your own server
neutral: use your own wrapper (w/ some light programming)