John Mueller, one of Google’s lead Webmaster Trends Analyst, equated press releases to advertisements. It was specifically asked if all links in press releases need to be nofollowed or just “links with optimized anchor text” in press releases need to be nofollowed. While John said it would be somewhat okay to have direct URLs linked within press releases that are followed, he did say to be safe, he’d recommend nofollowing even those links (i.e. the links that are not even optimized anchor text).
He did add that there is still great value to using press releases. The goal of the press release is to get the word out to the press about your new service or product. When the press hears about what you have to offer and if/when they decide to write about it on their own sites, those links do not need to be nofollowed. In fact, those stories written editorially are the links that Google values the most.
Google’s Matt Cutts has said that links within press releases do not pass value. Although SEOs have proof that this is not true, it does seem that Google is taking even more direct action against abuse of links within articles and press releases that are paid.
The outcome of the questions from SEOs around the new link schemes documentation change was to nofollow links within press releases.