Companies and brands are looking to engage via social-media, and there are loads of resources. Are there any must-read blogs from your RSS that provide current, practical information (case studies and best-practices) on how advertisers and marketers are engaging appropriately (or not)?
As mentioned earlier mashable.com is one to check out for sure, here are two others worth watching:
http://www.toprankblog.com/ <has both regular online marketing and a lot of stuff on social media marketing
and
http://www.scottmonty.com/
Hope this helps.