You will find one of the most asked question in the world of linkbuilding has to be "should I ping my site or the pages that I have added my Backlinks?" I will guarantee that you will find very strong theories on both sides of the line.
To ping: It is said that pinging will allow the search engines to spider your site sooner and increase the chances of indexing the page if it hasn't already and therefore spidering and indexing your url.
Not to ping: This theory holds it weight on the basis that the best results come from more natural and slow discovery of urls and therefore allowing Google to spider and index your url. They tend to use the analogy that Backlinks are just like an in person referral and while found slowly and naturally it would seem as though these Backlinks are cordially being mentioned to the search engines one at a time while pinging would be compared to thousands of people from around the world screaming "add this link" or "we recommend this website" all at the same time.