SEO techniques can be classified into two broad categories: techniques that search engine companies recommend as part of good design ("white hat"), and those techniques of which search engines do not approve ("black hat"). The search engines attempt to minimize the effect of the latter, among them spamdexing. Industry commentators have classified these methods, and the practitioners who employ them, as either white hat SEO, or black hat SEO. White hats tend to produce results that last a long time, whereas black hats anticipate that their sites may eventually be banned either temporarily or permanently once the search engines discover what they are doing.
For example, we regularly create content on the topic of "SEO," but it's still very difficult to rank well on Google for such a popular topic on this acronym alone. We also risk competing with our own content by creating multiple pages that are all targeting the exact same keyword -- and potentially the same search engine results page (SERP). Therefore, we also create content on conducting keyword research, optimizing images for search engines, creating an SEO strategy (which you're reading right now), and other subtopics within SEO.
Many blogging software packages automatically nofollow user comments, but those that don't can most likely be manually edited to do this. This advice also goes for other areas of your site that may involve user-generated content, such as guest books, forums, shout-boards, referrer listings, etc. If you're willing to vouch for links added by third parties (for example, if a commenter is trusted on your site), then there's no need to use nofollow on links; however, linking to sites that Google considers spammy can affect the reputation of your own site. The Webmaster Help Center has more tips on avoiding comment spam40, for example by using CAPTCHAs and turning on comment moderation.
This post and the Skycraper technique changed my mind about how I approach SEO, I’m not a marketing expert and I haven’t ranked sites that monetize really well, I’m just a guy trying to get some projects moving on and I’m not even in the marketing business so I just wanted to say that the way you write makes the information accesible, even if you’re not a native english speaker as myself.