"There are many – probably way too many – porn Web sites which are basically just links to other Web sites. I think they're called gallery sites."
"My question is: How do these sites make any money? How do they pay for themselves? As far as I can see from my limited experience, they don't sell anything. All they offer are pictures from other Web sites. You click on a picture and you're taken to another site, which has pictures that you click on and you're taken to another site, ad infinitum. None of the sites seem to be "pay" sites...at least, all you do is leap from gallery page to gallery page without any offer to join or become a member. What's going on here? What's the purpose?"
"And, equally frustrating, if one is interested in a particular picture, and in seeing more of that series, there seems no way to get to it... because, all you do is go to another gallery site, with more (some different, some the same) pictures to click on, and continue on to infinity."
A Quick Look
As a consumer and not just a producer of online adult entertainment, I understood his confusion, and tried to explain in layman's terms what he might be seeing, and why. Since this information might be of use to those trying to enter and understand the market, I present it here for your consideration:
You are most probably visiting a Thumbnail (or Movie) Gallery Post (TGP/MGP). Movies Arena is a good example.
These are arguably the favorite type of sites among surfers looking for adult material, because they're free, and offer a virtually unlimited amount of content. There are by recent estimates in the neighborhood of 100,000 of these sites currently online. Many operators will own multiple, often similar properties.
The original idea behind free porn is the same business model as the lady handing out bites of kielbasa at the grocery store; you like the sample, you buy the product. This has gone badly awry, as some folks have an "if a little is good, then more is better" attitude, while many webmasters are notorious for copying, rather than innovating, creating a tremendous glut of "me too" free content sites, and finally, surfers these days are smart enough to realize that (almost) all the porn they could ever want is available for free at these TGP sites.
These sites typically feature sponsor-provided galleries given to them by pay site owners wishing to market their offerings, and many TGPs still feature submissions from other webmasters, which is how they originally were conceived to operate – but this practice is fading due to the 'cheating' done by primarily off-shore operators who change their galleries after listing to include things such as Trojans, spyware and other harmful nasties that we can all do without.
This is generally a sign of desperation over their inability to profit otherwise from this tremendous traffic source which runs in the tens of millions of web surfers daily.
Because there is so much free content out there (much of which is stolen and posted in violation of the owner's copyright), it takes some very compelling, original and exclusive content to make a membership site sale to this market. Folks keep trying though, because this is where the 'eyeballs' are.
As for "How do these sites make any money?" There are several revenue streams open to site owners: They may use direct advertising through banner ads, select text links, or other creatives. They may use the perviously mentioned sponsor-provided galleries that contain an affiliate code giving them credit for any membership sales thus generated (with an average payout of $30-$35 per referred signup). They might collect and sell e-mail addresses, sell items such as 'penis enlargement' products, and also link to live video chat, dating, or adult novelty sites (once again, in hopes of receiving a nice commission check).
The most popular TGPs sell gallery listings to submitters. For example, if a webmaster lists 35 new galleries in a daily update, but receives 300+ submissions from other webmasters hoping to find a slot in that update, the reality that this is a buyer's market hits home, and he can then sell his top x number of slots for y dollars, and use sponsor galleries for filler.
As for being redirected to different sites when you're trying to view a gallery because you like a thumbnail image or provocative text link, there are several possibilities. The worst case is that you have received a virus that is sending you to sites of the creator's choosing, rather than where you're trying to go. Another possibility is that you're hitting what are known as 'blind links' – so rather than going somewhere specific, you're following a generic link such as "Teen Web Cams" which could take you to any site, the choice of which is made by the TGP owner who will get a commission if you join there.
Overwhelmingly, however, the reason that you go to a different gallery post site instead of to the gallery you were trying to visit is because you were "traded." Traffic trades are the primary way in which most of these sites attract visitors. The back-end scripting assigns what is known as a "skim percentage" to the thumbnails and links (all of which are pre-determined by the site owner). Click the thumb three times (for example) and once you might see the gallery, the other two times you'll hit one of that site's trades. The site you end up at records your visit and then sends a surfer back to the referring site. Since new browser windows are typically opened in this process, one visitor to one site might get traded multiple times, returning an equal number of visitors back to the originating site.
This whole traffic trading process is automated, and the scripting quite sophisticated, developed out of the desire to have equitable trades between sites: I send you 1,000 visitors, you send me 1,000 visitors in return. Thus, there is no disparity in the traffic flow between larger and smaller sites.
Sometimes, a variant of this process known as the "Circle Jerk" will send you from site to site, automatically popping window after window in an attempt at capitalizing on revenue from "per impression" sponsors who pay based upon the number of times an ad or site is displayed. This is pretty lame, in my opinion, because the last thing a surfer in the midst of this online Hell is going to do is pull out his credit card.
I hope this helps you understand the basics of gallery sites, the tactics they use, and why.
I'll echo this last sentiment, as I see folks posting on our and other message boards, asking these same questions. Hopefully, this will point you in the right direction, or at least, ease some of your confusion.