The "blog ping" switch enables pings on each new topic added. Once the switch is enabled, you can edit the list of sites to ping at Admin Panel -> Topics -> Topic Settings (near bottom of left column). There's a default list of several popular ones.

These pings are normally for blogs. Put simply, a ping notified blog search engines that you have a new entry for them to index. For information about what a ping is, see http://en.wikipedia.org/wiki/Ping_(blogging) . For discussion of possible uses in WSN, see www.webmastersite.net/forum...on-new-additions-8840.html