Press release sites have never been subject to the same measures of QA that have been applied blogs, etc. – a criticism I’ve often heard levelled at parenting bloggers is that they’ll write about absolutely anything. I can hardly imagine that letting absolutely anyone write about absolutely anything on a website is going to make it a good target to acquire links from. Bloggers have a vested interest in maintaining the quality of their sites – marketers publishing press releases are guests in several other people’s websites, often several times per week.