Been a ton of some rookies (same day accounts) bumping threads anywhere from 3 months to 2 years old, across multiple boards. Typically one angry post and they move on. What's going on here?

[Edit to add examples:]
http://texags.com/forums/61/topics/2058391/next

http://texags.com/forums/34/topics/2074952

http://texags.com/forums/61/topics/1617544/last

http://texags.com/forums/38/topics/2497134/last