Pinging a feed isn't the same as pinging a blog.

FeedPing.com is the brainchild of Matthew Stephens and Joey Mazzarelli. they started the site to fulfill a need for many of the new RSS developers who didn't own blogs. They believe that RSS is the future of Internet content syndication and felt obliged to help get the feeds out to the masses.

Pinging a feed isn't the same as pinging a blog. Pinging a feed simply submits the feed to all the feed directories so that it will begin to track the syndication.

How will this increase traffic to my feed?
Submitting to the directories will allow people to find your feed easier and thus increase subscribers and traffic to your site.

What's the difference between this site and other ping sites?
Other ping sites are for blogs, not feeds. They are meant to update blog directories with your latest entries. This site is meant to submit your feed once to all the feed directory sites and have them track your updates automatically.