Here are some great posts I recommend you read:
General SEO stuff…
Social Media Writing Differs from Traditional Web Writing
AOL Facelift (see a theme on these two? hmmm…)
Microsoft AdCenter impressions bug still being fixed
Search, not Social, is how people find products online
All about Google and related…
Google Local Integration Game Changer
Google Places Search – Losers and Winners
Places and Local Link Building
Using Viral Video and YouTube Advertising Together
Top 15 Eric Schmidt Quotes (this one’s just scary/entertaining)
Google Instant isn’t changing search behavior
Twitter…
Twitter Testing Promoted Tweets in Timeline (greeeeaaaaat)
AdWords Call Metrics – new stuff is good.
Oldie but Goody for history buffs like me…
Let’s end with one that is itself a roundup. Some of the same posts I’ve listed are mentioned here – seems we’re in agreement that these were major posts this week…
http://www.smallbusinesssem.com/october-10-best-searchmarketing-posts/3705/