Well, its the equiv of the SEO optimized.. but I don’t pay them for SEO optimizing the release, that’s hype, I can do that myself 
So I pay them just to be able to ad links, images, be on the front page etc. Then I fix the PR up, add the right tags, the links, and an image if the customer wants it. (generally a logo) .
The other benefit here is that I use my contact info, so i get the telemarketers and the spam emails lol .. see how thoughtful I am! 
LadyH