http://www.zdnet.com/article/hacker-steals-45-million-accounts-from-hundreds-of-verticalscope-car-tech-sports-forums/
If you're registered on any of these sites and re-use your login details elsewhere then I'd recommend updating your password anywhere it's used.
The stolen database contains close to 45 million records from 1,100 websites and forums hosted by VerticalScope, a Toronto-based media company with dozens of major properties, including forums and sites run by AutoGuide.com, PetGuide.com, Techsupportforum.com MobileCampsites.com Pbnation.com and Motorcycle.com and TopHosts.com
If you're registered on any of these sites and re-use your login details elsewhere then I'd recommend updating your password anywhere it's used.