Matt Cutts: links from press releases do not effect on positions | News
Old and still quite common method to get links to your website – press releases.
Usually, “writers” (SEO experts) contact companies that distribute press releases and in every press release carefully inserted a link to the appropriate site. In this case, the bet on what other news outlets have reprinted this press release and keep active links in their versions of the material.
However, even if all of this will happen, according to Matt Cutts head of Google's Webspam team, links from press releases still will not give a positive effect on website positions. So, there is nothing to do as remember times when press releases were reliable “tool” for website promotion.
This was a Google spokesman wrote on forum.
So, press releases itself have some benefits: your company or service learns more media, bloggers, etc. But links to press releases, as such, according to Google, will not affect website positions on which these links lead.