As I noted elsewhere, I'm looking at using Goodreads as a catalog system for my fairly extensive library.... here's a widget courtesy of the Goodreads people that gives a taste of some (I've only entered about 800 so far) of the books in my collection, in this case those I've tagged with the term 'cybernetics'

or, to see my complete 'cybernetics' shelf, click (and scroll down past tags see books) :

I think I've finally found a web system to catalog the books in my library!

When I was part of the early beta testing for Ning, I had high hopes for that platform. Unfortunately, at least in my mind they gutted the search capability and moved from the idea of a multi app based platform to a social network more based on blog and forum technology... not doing either particularly well at first (but I admit that I haven't really given them a look since it became obvious that they were no longer actively moving in the direction I had so eagerly participated in during the beta days).  When it finally became impossible to ignore facebook anymore (ok even then I didn't jump on board until the "web shaking news" they they had become an 'application platform) I signed up and tried some of the book/bookshelf/kibrary appications but found them pretty well to be toys not real applications. But just a few days ago another Tangler user pointed me towards "Goodreads"  ... as you can see in the conversation below, I have adopted it and have rapidly been adding my books to it.... and it turns they do have a facebook widget (not the full application, but access can be given to it through facebook).

Here's the conversation going on in Tangler about it (feel free to sign up to Tangler if you want to take active part in the conversation).