This page contains a list of companies that are purported to have "fired, threatened, disciplined, fined or not hired people because of their blog."
1.) Delta Air Lines
2.) Wells Fargo
3.) Ragen MacKenzie
4.) Starbucks
5.) Microsoft (some say yay, some say nay)
6.) Friendster
7.) the Houston Chronicle
8.) the St. Louis Post-Dispatch
9.) Nunavut Tourism (Canada)
10.) the Committee on Degrees in Social Studies, Harvard University
11.) Maricopa County Superior Court of Arizona Self Help Center and Library
12.) Mike DeWine, US Senator (R-Ohio)
13.) the Durham Herald-Sun
14.) Kerr-McGee
15.) ESPN
16.) Apple (according to this blog entry AND this article)
17.) Statistical Assessment Service (DC nonprofit)
18.) Minnesota Public Radio
19.) The Hartford Courant
20.) the International Olympic Committee (barred athletes from blogging during the Olympics last summer)
21.) Health Sciences Centre, Winnipeg, Manitoba, Canada (?)
22.) the National Basketball Association (NBA)
(via Apophenia)