Symantec has released it's December State of Spam Report. In it they note that in November spam increased to 72% of all email traffic. The report also notes some seasonal spam trends:

Penny stocks use Thanksgiving holiday captions in subject line - spammers using common personal Thanksgiving-related words in the subject of emails

Replica products a favorite for spammers this holiday season - replica gear has always been a spammer favorite. Spammers are marketing their wares using seasonal words in the subject lines of their mailings

Spam begins to snowball - spammers collecting email addresses by using a funny .gif that shows a snowball hurtling at you through your computer

Christmas freebie anyone? - spammers taking advantage of the season to market "free" gift cards for well known companies

Seasonal lotto scams - in a scam targeted at UK end users, spammers have updated a lottery spam email for a Christmas Bonanza special

Check out the rest of the report for more analysis and trends!