Display ads in social media have been getting a bad rap for awhile now. While many brands have had success marketing on social networks, purchasing display ads in the space does not always appear to be a great investment. 

But this week, Facebook announced that it has positive cash flow for the first time. The company met the 300 million user milestone this month and has reached profitability ahead of schedule.

While the company has gotten some bad press for the slow growth of its ad business, clearly some companies are finding success by investing in Facebook display ads. 

So what advertisers are making bank on the social net?

While social users enjoy clicking around on lots of things on Facebook, things they don't like clicking on are ads. Click through rates on social networks are often below 1%.

But this Spring, Business Insider and Fred Wilson estimated Facebook's reveneu to be around $550 million, with $125 million coming from brand ads, $150 million from Facebook’s ad deal with Microsoft, $75 million from virtual goods and $200 million from self-service ads.

The consistent revenue stream from Microsoft is certainly helping Facebook's bottom line, but smaller advertisers are using the service and — importantly — returning for more.

read more@ Meghan