A small number of ads began rolling out on Graph Search on Wednesday. Rather than being targeted to the user's queries, however, they are based on the same targeting methods used for Facebook ads—things such as age, gender, interest and location.
The new ads are just a test, a Facebook spokesperson told CNBC. But Facebook CEO Mark Zuckerberg had hinted earlier this year that Graph Search could become an opportunity.
The social network could join Google, Microsoft and Yahoo by cashing in on its users' search activity. It could introduce search-based ads that use keywords from a query to generate targeted ads that appear at the top of users' results.
(Read More: New Twitter Tool Lets Advertisers Target Tweets)
That could mean big money for the company. Search ad revenue totaled $16.9 billion last year, accounting for almost half of all digital ad revenue, according to the Interactive Advertising Bureau.
Facebook isn't the only social platform that may be looking to cash in on keywords.
Twitter launched a tool Wednesday that lets advertisers target its users based on keywords in their tweets.