There was a brief mention in the PG monthly news letter this morning of changes to the website. Next time you visit, note the icons in the upper right corner of the webpage. Next to the donate buttons (Paypal and Flattr) there is a link, and if you click on it you'll go to their.
This isn't the best design, but if you want to share what you're reading on Project Gutenberg, you can. Right after you download the ebook, go to the social page and you'll be offered the option of tweeting or posting a Facebook update. The tweet will look something like this:
Project Gutenberg also has a Twitter account and RSS feed where they post mentions of newly converted (or recently updated) public domain ebooks which have been added to the collection. You can find those on the social page as well.