Not completely functional yet, but still something to show: http://identi.fi (identifi/identifi). It's a Rails UI for the Identifi client, which is built on bitcoin-qt codebase. Basically, we flood trust packets throughout the network. Nodes give the priority to packets that are authored and signed by someone from within their web of trust.

Feedback, technical suggestions and help with development is very welcome. The code is available on GitHub.