It happens a lot lately: you’re using a search engine to find results, and you click on a result, only to find it’s actually a paid result, not an organic one. While advertisers and search engines are required to identify paid results so they can be differentiated from organic results, it seems like the markers become harder to identify with each passing year.

This troubles the Federal Trade Commission (FTC), which has updated the 2002 guidelines on ensuring that paid results are kept separate from organic results by sufficient labeling. The new updates were sent in the form of letters to major search engine companies warning them that the necessity to separate paid and organic results was still valid.

“Although the ways in which search engines retrieve and present results, and the devices on which consumers view these results, are constantly evolving, the principles underlying the2002 Search Engine letter remain the same: consumers ordinarily expect that natural search results are included and ranked based on relevance to a search query, not based on payment from a third party,” wrote the FTC.

The agency informed search engine companies that failing to clearly and prominently distinguish advertising from natural search results could be considered a “deceptive practice.” The agency told the companies they must offer “visual cues, labels, or other techniques to effectively distinguish advertisements, in order to avoid misleading consumers.” The letters stated that it is the search engine companies’ responsibility to ensure that disclosures commonly used to identify advertising are noticeable and understandable to consumers.

The FTC noted that it had done studies with individuals using today’s search engines, and that it found that people are increasingly incapable of differentiating paid search results from natural results, particularly when it comes to “top ads,” and advised that noticeably different shading should be used for the backgrounds of ads and genuine search results. In fact, about half of those studies had trouble differentiating between a top ad and an organic search result.

“Given the importance of distinguishing advertising from natural results in a clear and prominent manner, we recommend you review this letter and make any necessary changes to conform to this guidance,” stated the FTC.