Pinging servers such as ping.fm and pingoat.com others can increase the backlinks or the ranking in google
It creates attention for the search engines, but some ping services like pingoat have a page called "recent pings" that lists all the sites who have pinged them (with a link). This might count as a backlink?
By doing pinging, you just inform larger servers that you have updated your website. It also helps to increase traffic to your website.
I'm yet to be convinced, just think about the thousands if not millions of people all pinging millions if not 10's of millions of links each day - does it really make a difference if you ping?