The anchor text that you use to link to your website is very important.  From the best of my research if your anchor text corresponds with your product you will do very well.  If your anchor text does not match it then you will still get search engine traffic from this, but your queries will not be specific to your product.

One test that I did not to long ago was to get a page to rank for some word that I made up. The rules of the test were that the made up word could not be located anywhere on the page.

Well it turns out that I eventually ranked for my made up word, and this was done only by specifically manipulating the anchor text.

Also, (getting a bit off topic here.. but it must be said) there is somewhat of a misconception that untargeted links aren’t worth anything.  Sure, if you get a bunch of links with the anchor text “Cool Website,” these won’t help you rank well for your keyword “Stock analysis.”  What they will do, however is send pagerank to your domain name that you can then “transfer” to other pages of your site using targted anchor texts.  So, always do your best to get as many links as possible.  They will all help you out in someway.

If the content of the page the link is placed on is not related to your content, the link will not be worth as much, but it is still worth something… and this will most likley be a viable process for tipping the scales in your favor.

On one of the tests that I ran, I linked Domain A to Domain B by placing an insane amount of links (something like 300,000 links from A to B).  Resultingly, there was a dramatic effect: Google did not count all the links (Yahoo counted more), but these links were still enough to push the domain past my competitor.

Another hint of advice that I can give is to verify the links are placed on a page that will remain indexed within Google.  This goes without saying, but if the pages you are on get removed, or are not worth anything, your links will also be worth nothing.