Facebook unveiled a number of new opportunities for advertising on their social network today, the biggest being the ability to post ads to mobile devices, which they had not yet been offering.

Facebook calls the new ad opportunities “Premium for Facebook” and it opens up the following placements:

    Larger ads on the side of the Facebook home page that users see when they first log in Ads that run inside the Facebook Newsfeed Ads on mobile devices Ads that appear when a user logs out of Facebook The ability to run video ads on all these placements

We were not aware of just how many folks were using Facebook on mobile until they filed for their IPO. According to the filing, there were 425 million monthly active users of Facebook’s mobile products in December 2011. This gives advertisers another opportunity to get their products in front of Facebook users. Mobile is growing at an incredible pace. eMarketer estimates Facebook’s ad rev will pass $5 billion this year, accounting for 6.5% of all online ad spending. That doesn’t even factor in the new ad opportunities they’ve unveiled today.

Here’s more on the way Facebook makes money from Reuters TV: Tech Tonic