A picture is worth a thousand words.
This is a random thought, but where are the pictures. Most java.net projects, even the ones that have some visual user interface (as opposed to a library like Rome), don't have screenshots or diagrams. When I come to a new project I want to quickly know what it's about and if it's quality. A picture really helps with that. I know it sounds bad, but if there's a picture then it can first tell me if these people are serious and active, or if the project dead. A picture can also convey a lot of information more quickly than a paragraph of text will. When it comes to visual projects, say a date picker component, then this is doubly important. Show me a picture! It just takes a bit of time and it really helps grab my interest.
Of course I am a primary offender here. My own project Flying Saucer has a cute logo but no screenshot. It's an entire library for rendering things visually, and there's not a single screenshot on the site! We are close to shipping R5, which I hope will be our watershed release showing that it's ready for primetime, and I promise that the first thing you see on the site (well, after the cute logo) will be a drop dead gorgeous screenshot!