Search engines need you to have a lot of original and keyword related content. Visitors stay longer and will click on more links or go through more of your pages, if you indeed have the said content. Problem is, you don't want that - You want to kick the surfer off your digital premises and on to the sponsors' property. After all, that's what it's all about - Sending visitors to sponsors, where they sign up. While these two factors may seem to be in opposition, that's not the way it works. It's just plain, simple sales methodology.

STAGE 1 : MENTAL BOOKMARK

When a visitor first finds out that your site exists on the net, it's important to build trust. By providing what the visitor came looking for - be it a gallery with pictures or videos, a bio page or just categorized links to free porn sites or free hosted galleries. While this may seem to be just feeding a freeloader, it does tell the surfer that your site has what he looked for. Which means that the next time he sees your site listed for a keyword, he'll be selecting yours out of the other 10 results for a further look-see. Thta's what we can call a 'mental bookmark'. Besides, he just might click through to the sponsor.

STAGE 2 : NEW LINKS

While it might still be called hoodwinking if you pack of a return surfer directly to a sponsor or trade, there is a way to do this - which doesn't involve any hoodwinking, and which maintains the trust initially developed. Use a 'New Links' page with direct links to sponsors. Example: A sponsor comes up with a new model, and she has her own page or website, so you link directly from the 'New Link' page to the model's page.
This has multiple advantages. I'm assuming here that your site can recognise a return visitor by means of a cookie or another script. The return visitor has likely seen what you have to offer, and will be looking for something new. So, you send him off directly to the new links page, instead of your home page. All he's going to do is take a look at the 'new links' and click on one of them.

STAGE 3 : IN-GALLERY ADS

Let's say he's obstinate and wants to see your category links of free porn again. He clicks through from the 'New Links' page to your Home or Category pages ( links to which you must provide on the 'New Links' page ). Now what you need to do is - hit him with ads. I have tried out a series of methods ( including popups ), and found this one the best - Introduce a sponsor tour link, in a iframe, between the thumb and the full image or between your link and the trade. Put in a 'SKIP THIS AD' link to the full image above and below the sponsor tour iframe.
Let's say, for example, that the surfer clicks on a link to 'Gallery XXX'. Now you need to maintain two versions of the gallery index page - one html ( normal gallery, with thumbs linked to pics ) and one PHP ( with an ad between thumbs and pics ). First timers get sent to the HTML version and returning visitors get sent to the PHP version. Sort of gently reminding the vistor that there's more at the sponsors' premises than yours. Even better if you put in different tours of the same model for different thumbs. Between your links and trades, put in a random but related niche sponsor tour iframe with a 'SKIP THIS AD" link to the trade or hard link partner.

The 'SKIP THIS AD' routine may not work for mainstream sites, because the subject matter of the ad is hardly what the user came to the page for, but in the case of adult sites, a sponsor tour page is the most directly related matter to what the surfer is looking for in your page or gallery. One can only hope that this form of advertising catches on and is accepted by TGP's.