Lots of ports in macports are installed as library dependencies of the other (application) ports, but uninstall those application ports doesn't uninstall corresponding library dependencies. As time goes by, lots of such library ports become orphon and is just a waste of space. So I wonder if there is a way to find them out.
Thanks.
There is a package/script you need called port_cutleaves. I think it's available directly from macports or fink. Either way your problem is orphaned dependencies, and this should remove them, sorry I don't have details of usage as I'm away from my macports install.
Update: This link might help you, it's a cheat sheet. http://www.jbmurphy.com/2011/02/17/my-mac-ports-cheat-sheet/