Why Don't We Hear More About GNU Server Pages (GSP)?

Ozten asks: "I am currently looking at GSP and trying to convince the big e-commerce company that I work for that Open Source technology doesn't mean more maintenance than large packages on the market, such as Blue Martini or IBM Websphere. I am looking for facts and firepower on GNU Server Pages, but info is sparse except for bit mechanics and its links. You would think that with a high profile site like the Star Wars Shop using GSP, it would get more notice. Any other facts out there? GSP seems like the best free software since gnu-SlicedBread, where is the hype?" Actually, I would like more facts than hype. With production sites using this technology, I would be interested in hearing how well the things have held up, in addition to any advantages and disadvantages over popular solutions like ASP.