Photos on a web site fall under the same contexts as other kinds of publishing: editorial, commercial, or artwork. If you put your photos on your own website, this is a case where
you are the publisher. However, publicizing photos as being "for sale" does not require a model release so long as you are only selling the photos, not promoting a third party product or service from yourself. Nor can you attribute (or imply) that someone (in a photo) advocates your business, an idea, or anything. You can sell these photos too, although the buyer's use of the photos need to be considered. Again, see
Model Release Primer for a detailed discussion.
The point is, photos of people should not appear to express an opinion. If they do, a release is required. An example might be a photo of a woman with the caption, "I'm Jan, and I love to stay at the Jimminy Glick Hotel." This is advocating a company, so it requires a release. If the photo happens to be on the same page as other ads, but clearly not associated with the ads, then no release is required. Ads on web pages are very common, and it's rare that people associate a relationship between the advertiser and the content. However, some people try to push the limits, especially when it comes to political and relgious views.