Now it seems that there are going to be ads in these search results. These ads will appear in the form of sponsored posts. It is currently testing this new ad placement out, and will soon be rolling it out to all sorts of advertisers. Basically, when you try to pay for an ad on Facebook you are going to get an option that you can select. This option will allow your ad to be displayed in the search results. During the beta run this feature will only be offered to advertisers on the North American continent, however it is probably that Facebook will start offering it to advertisers all over the world pretty soon.
In an attempt to protect the user experience, Facebook will be clearly marking sponsored search results. Users are also going to be able to ask why they are seeing a particular search result. This will enable users to figure out whether or not a particular search result is legitimately relevant to the query they entered into the search bar or if the result is only showing up because of the fact that someone paid to have it there, thus making it somewhat less legitimate than those results that are appearing without the sponsored tag next to them.