There is a very interesting discussion thread over at Google Groups involving Matt Cutts.
Basically, a website owner complained that his website was penalized by Google and many rankings where lost (-xx penalty). After a leangthy discussion, Matt Cutts joined in and pointed this out:

ShyBoy, have you been collecting backlinks in any unusual ways? It
looks like [...]

Have a limited online marketing budget? Here are a number of ways to promote your website for free!
Free Online Marketing Tips and techniques:

Start a blog. Use a free service like WordPress or Blogger. This is an excellent way to attract targeted visitors to your domain. It is a long term project, so be patient. Traffic [...]

A case study:
You hear it and see it all the time in the domaining industry. A hyphen in a domain will decrease the value of that domain name and search engines often devalue hyphenated domains as these are often ‘copycat domains’ or 2nd grade content domains. Although I agree this is true in some cases, [...]

This is something I have been giving considerable thought to the past few months. I did not get around to sharing some of my 2008 SEO and online marketing predictions yet but since it is march already and there is about to be a big shift in the seo and online marketing industry this year [...]

Link Baiting is in essence an advanced form of link building. Link Baiting is pretty much like baiting a hook: A fisherman would bait up a hook so that a fish would be more inclined to take a bite. It is the same with link baiting. You throw out a link somewhere, like on one [...]

Wikipedia did it 12 months ago and del.icio.us 6 months ago and now Flickr is also following suit. Nofollow tags have been placed on all external links (links pointing to other websites). This is in response to people (spammers included) using these sources as a form of link building playground to point links from these [...]