It still comes as a shock to some community members that WordPress.com runs advertising on free hosted sites, unless you’ve purchased the annually renewable No Ads upgrade to remove them. This is stated in the Terms of Service that everyone agrees to when signing up for a website here.
Recently however, WordPress.com has made a much appreciated step in making site owners more aware of possible ads. Here’s what I saw earlier when previewing a post on one of my other sites:
Clicking on the “tell me more” link brings one to the page explaining why you might be seeing ads.
Again, advertising is only shown in a limited number of places. If you are logged into WordPress.com you won’t see ads on sites unless the site owner is part of the WordAds program. The most common way visitors will see ads is via search engine results on a single post.
So while WordPress.com may not be entirely ad free for logged out visitors, WordPress.com is helping site owners be more informed about their advertising choices (Ads, No Ads or WordAds).
Update: The above notification also appeared after clicking on a New Comment notification I received, so I do wonder if ads are going to become more prevalent than before.