Here are some of the better posts for December:

Stores Seeking Shoppers Find E-Mail Outdraws Facebook – Bloomberg
“e-mail provided $39.40 in sales per dollar of advertising this year, followed by $22.38 through Web search, $19.71 from Internet display ads and $12.90 from social networks, according to the Direct Marketing Association.”

How To Create Killer Product Pages – Get Elastic
And Free Shipping again remains a key reason for shoppers to purchase at a particular site.

7 Critical SEO Errors of E-commerce Websites – KISSmetrics
Good review of the straight forward things to improve SEO for your products.

Black Friday and Cyber Monday 2012 Stats for the Small Online Merchant – LexiConn
Insightful analysis of how the smaller merchant did this holiday season.