I don't care who you are and what your level of expertise is there are some industries and words on the net (non adult and gambling) that are so competitive you will not stand a chance if you are not a darker shade. The competition can be so fierce in these niches you better have the dirty alter ego ready to play if you want to make any headway. I think by competing in these industries there is a lot to learn that will help you sharpen your skills for your legit sites.
Take for instance Myspace Layouts have you run a site comparison on the sites in the top 10 or 15. Most of them aren't even a year old, and the average Backlinks for a site is over 500k. All kinds of shady stuff is going on, trading links with everyone and their mom, buying links from any site for any price (I know of a guy that spends 18k a month on links) and just about everything else. My theory on all of this is that some industries Google looks at what is going on across the board and lets it slide cause everyone is doing it, there is not enough sites that are pearly white so its filters are more lax. That is my theory, just because I know that pretty much every site ranking for myspace words is using some sort of link scheme whether it be Co-Op or Link Vault or something else. Or in this instance it could be that Google's algo could care less about what goes on for an entire industry whose keywords are based around a brand name or it could be that the ghetto has more crime than the sub-burbs and that petty theft is overlooked.
Even outside of myspace there are words where you better bring your gray game or you will not see the light of the top 50. With all this talk about link buying ethics and all that as it relates to seo, it reminded me that there are industries outside of the 3 p's that are so insane that you better be ready to pull out all the stops if you wan't to survive. You know the saying, "all's fair in love and war" these industries are so competitive it is literal war with hundreds of thousands of sites. There is so much traffic and the rewards for rankings are so great that cut throat needs to be at the top of your To Do List. When one of my sites was on page 3 for Myspace Layouts I got over 30,000 visits a month just off of that one word.
I think the only white tactics that could have any weight in these industries would be some awesome viral campaigns that drove thousands of links a day to the site. Regardless you should check the avg seo going on in your target keywords and if the avg. number of backlinks is over 500k per site you may want to dye that hat a little darker.