As Wired reports:
The four patents at issue allegedly cover basics of online commerce, including recommending products to a user based on what they are currently looking at, and allowing readers of a news story to see other stories based on the current one. Two other patents relate to showing other information on a web page, such as news updates or stock quotes.
Obviously, the less-than-clarifying Bilski decision from the Supreme Court isn't deterring him.
Read more details (and see a copy of the lawsuit itself) at Wired.com here: