Back Links Are Changing...

[Halfdeck]

I have about 100 adult and 100 non-adult sites

That means most of your sites are not worth linking to. How much time could you devote to each site if you have 200 sites? In a span of a year, a little over 1 day per site.

people always suggest linking pages together with PR and that have the same content areas.

If everybody in the adult niche linked freely to relevant sites they thought were good, those links will improve alot of sites' rankings. Wikipedia links out to millions of sites and look where they are the the SERPS - and they were in that comfort zone long before they decided to nofollow everything.

Instead, we try to think of ways to prevent traffic leaks and trade links to boost TBPR by linking up "relevant" pages (like Google cares whether a page is about anal sex as opposed to watersports - porn is porn) or build thousands of low value recips, like building castles in the sand.