Stack Exchange, “a network of free, community-driven Q&A sites,” now has a Library and Information Science site in beta. Most of the library Q&A I have seen has been through LinkedIn groups’ discussions (mostly ALA), so this seems like a great forum for detailed, professional questions.
Because librarians are all about sharing knowledge, I’m optimistic that this site will be successful if enough library professionals know about it. So, librarian-friends, check it out! Read the FAQ before jumping in and asking/answering.