Submitted by Alexis Wilke on Sun, 01/22/2012 - 15:42
I often receive spam in my mailbox and on my websites. It is expected that emails will include one link that's repeated several times so the readers are much more likely to click on it at least once1. If they don't click on the first one, they are likely to click on the second or the third. When they skip all of those links, maybe they'll click the one in the P.S. area? This technique makes it easy to funnel people to a specific location on your website.
Now this is completely different from good SEO.
In your website you can include links to other websites. This is called passing juice. The more links go one way or the other, the more juice is being passed.
Of course, the best links are those that come to your website. Therefore, the more places you can find to include a link that points to your website the better2. Especially if that place is very highly ranked (i.e. say the page you want to post on has a Google rank of 8, one single link from that page is likely to make your page go higher at once.)
Spammers, however, do not really work that way. On the Internet they post messages with links back to their website without consideration for clean SEO. Although they may put a nice message (a message that brag your product, post, or website) in their comment, they will also include their link to a website you most certain do not want to be associated with.
This picture shows you exactly what NOT to do. Note that SEO must be used to increase the rank of ONE page. You want ONE link to that ONE page. Whether people click on the link is not relevant to the SEO realm. The fact that the link is there and does not include a rel="nofollow" gives you juice from the source website. As we can see, that spam message has 3 links and all 3 are to completely different websites.
The best of the best, in terms of links, is when someone else creates that link on their own, without asking you to do any anything for them whatsoever. However, that's a very slow process. If you want to increase your rank quickly, you want to be pro-active and create your links.