The above poster is correct. But perhaps we can have a discussion about interesting features/idea? And later these refined ideas can be ticketed to Calibre. That way David is getting more refined ideas and not something like "This would be great lolzors!" in his tickets. It also enables David or other programmers to chime in if they wish stating why a certain feature is not possible and can people please stop asking for it :P
For example. I would love to see a way for Calibre to upload the metadata of all the books you have to a web page (say Calibre for ease atm) and combine that with the metadata of all the other Calibre users so there's a go-to page for Calibre users to get metadata for their new books. Possibly also have a way to track 'books read' in Calibre so users can then see what the most read books in Calibre etc. are. It would also be handy for combining reviews. That way people could review their books in Calibre and have it uploaded to the website. It would also help with the star ranking system as well, because you'd be drawing from a larger pool of people.
But that's most likely impossible. So submitting it would most likely be a waste of time