The WSJ today notes that Facebook lags Myspace substantially in ad sales, despite having surpassed MySpace in usage:

[Facebook] … says 70 of the U.S.’s 100 largest advertisers have advertised on its site since 2007. But its share of total number of U.S. online display ad views was just 1.1%, according to market research firm comScore Inc., in its most recent report in June.

News Corp.’s Fox Interactive Media Unit, which includes rival MySpace.com, is the market leader with 15.9% of display-ad spending, according to comScore.

I believe that this is because most of the ads the Facebook sells are not standard units, unlike most of the ads that MySpace sells. As I’ve mentioned before, new forms of advertising are hard.

However, I am excited about the new engagement ads that Facebook is now selling:

The Palo Alto, Calif., company is rolling out a new ad format called “engagement ads” that further blurs the line between marketing and social networking.

The new ads appear on the main screen when a person first logs in to Facebook. They prompt a user to do something within the ad, such as comment on a movie trailer or RSVP for the season finale of a TV show.

This could be the first move towards a new standard for social media advertising. As I said previously:

The thing that differentiates social media sites from other forms of online media is not just user generated content, it is also that users are willing to affiliate themselves with brands. This takes many forms, from friending Scion on Myspace to putting a Natasha Bedingfield style on your Rockyou photo slideshow, to buying one of your Top Friends a Vitamin Water. These willing user affiliations/endorsements of brands are clearly valuable to marketers of those brands. Right now though, these deals are being negotiated on a one off basis; they look more like business development deals than selling ads off of a rate card. It will take a while for the social media industry to establish standards for selling this incredibly valuable inventory to brands, but I suspect that this will happen over the next 12-36 months.

Facebook’s engagement ads are potentially the first step towards defining what the ad unit will be (prompting a user to take an action that affiliates themselves with a brand). Flixster has had good success with this concept in many of its campaigns with movie studios. I think this concept could well be the basis for a new standard unit for social media, and I hope that the rest of the industry gets behind it.