Advertisers are expected to invest $31 billion in online advertising this year, a 10% increase over earlier predictions. Research firm eMarketer says 2011 will mark the highest level of online ad expenditures since 2007.  A few more details from eMarketer’s survey:

* Search advertising continues to be the most popular form of online advertising, though display advertising is steadily increasing in popularity due in part to the rise of Facebook.

* Television continues to be the dominant medium for advertising, comprising 38% of marketers’ overall ad budgets.  Online advertising is expected to comprise 20% of marketers’ outlays this year.

* Online video advertising will nearly double from 2010 to 2013, making it the third most popular form of online advertising.

For a detailed summary of eMarketer’s report, click here.