Frequently you see discussions regarding certain SEO techniques being Blackhat or Whitehat.
I have always looked on it that the easiest way to determine that is to read the Google webmaster guidelines, and keep an eye out for what Googlers are saying. I think it is also wise to follow the spirit and not the letter of the law.
Cygnus who is well respected in SEO circles, though less frequently quoted than many notable people in the SEO field, has been around the SEO block multiple times.
So what about black hat? All that really means to me is using the unexplained rules of the system. It isn’t evil, it isn’t fraud, and it isn’t hacking. To do any of those previous nasty things would be outside the scope of aggressive, competitive, lateral thinking search engine optimization.
Read more on Lateral Vs Traditional SEO
It is an interesting read, however my belief is it is possible to be a lateral thinker and still stay on the lighter shades of SEO.
Just a simple example would be Technorati. They provide a useful tool for bloggers with a website full of 100% duplicate content. It is made unique by mixing the duplicate content up and niching it. You can do the same on your own blog by using extensive internal tagging and customising the different archives to look different (I still need to do the second part). WordPress.com take this a stage further and offer followable links from their tag indexes.
Another example might be intelligent use of dynamic linking or nofollow. Nofollow wasn’t intended to help control the distribution of pagerank to your older content, but doing so isn’t a dark art, but it might be looked on as lateral thinking. It can and should be used for many kinds of external links and how you manage your blogroll can be important.
Most popular posts lists are useful on blogs, but they don’t have to be your most popular post, you can make them most popular just by telling visitors they are ;)
Sure it is good to include some popular posts in the mix, but you can also intersperse some of your top earners. Those pages will for most blogs gain more pagerank being listed on the front page. The more times you link through to certain key pages, the more likely they will be popular anyway, depending on how you calculate it.
Update: For another take on this subject try Black Hat vs. White Hat vs. Grey Hat SEO: The Definitive Guide – Damn the megite SEO list is already becoming useful.
I don’t think this is a definitive guide, but it is another good point of view