This combination of the two applications (Semantic Radar  and SemWeb Ping Service ) may be of particular interest to the DOAP community - allowing to discover DOAP resources on the Web.
Semantic Radar - a Firefox extension that detects DOAP, FOAF and SIOC autodiscovery links and can also ping the SemWeb Ping Service.
SemWeb Ping Service - a web service that collects pings about newly discovered or updated Semantic Web resources. One of the ping sources is the Semantic Radar extension - thus you are collaboratively charting the Semantic Web in the background as you are browsing the web. Information collected by the ping service is available to whoever needs it. It has helped to find many DOAP documents - so far the ping service lists 190 DOAP profiles including Opera widgets, OpenLink Virtuoso and Apache projects.
You may find developers of these applications online on #sioc (irc.freenode.net
More articles about the synergy of these 2 services:
 Semantic Radar for Firefox and The Semantic Web Services
 Enabling SIOC for AI3 - Adaptive Information
All feedback is welcome. :)