Press Release Links Don’t Help Your Rankings
I wouldn’t expect links from press release web sites to benefit your rankings, however.
Does this mean that press releases are a waste of time? Certainly not. The links from your press release itself no longer seem to confer any link popularity benefit. However, a well crafted press release might catch the eye of a reporter, a blogger, or another interested person who may write about you and the material in your press release. Any link to your website from those secondary sources will almost certainly contribute to your link popularity and, in turn, to your rankings in the search engines.
We’ve been de-emphasizing press releases as a link building tool for some time, and this clarification from Matt Cutts just clarifies what we’ve believed for some time. If you have something compelling to say in a press release, by all means submit it to online press release websites. Just don’t expect an immediate benefit from them until others pick up your story and run with it.