Found a few good articles for you to review:

Gauging The Online Visibility Of SMBs by Hanan Lifshitz. Thoguht this was a nice follow up from his last article over at Search Engine Land

Twitter and Local Search: A Status Update by Mike Boland at Search Engine Watch.  One article that Mike mentioned in his post was Rest in Peace, RSS by Steve Gillmor where is discusses how Twitter is killing the RSS feed. Very interesting!

How To Use Twitter For Building Links by Nick Stamoulis

Local Search Ranking Factor Statistical Research by Brian Cater

Happy reading!