This is a rather unusual portal, and it doesn't quite resemble any other free ebook site or ebookstore. Initially launched in July 2012 with around 700 titles, this 18 month old service now boasts 2300 titles which are available to download for free. That's far fewer than the 45 thousand titles available on the main Project Gutenberg site, and that's not the only difference. The only ebook format offered by the self-pub portal is PDF, and the ebooks are still available as free downloads, with some CC licensed titles mixed in.
Yes, the only supported format is PDF, and yes, many of the titles are free to download but cannot be shared. I didn't really understand the limitations when this portal launched, and 18 months later I am still baffled.
It's almost as if PG started to build a commercial ebookstore for academic titles, and then let the project stall. This would explain the license and format restriction, but it raises questions as to why this is still a free service that doesn't support the formats desired most by users.
But in spite of the puzzling details, some authors are finding this portal to be useful. The collection now boasts titles from over 30 languages, including Latin, Japanese, Urdu, and even a couple photo book titles which should not be viewed after a meal.
The self-pub portal can be found at self.gutenberg.org.