Pinging isn't for promoting sites. It merely informs SEs that you've updated your blog/site and adds the site to the crawl list to be indexed again
I'll add to this. Most blogs (wordpress) already automatically ping new content, so there's no need to ping these. Pinging should primarily be used to get your backlinks indexed.
if you ping your website then it is a intimation to the search engines that your website exists.then there is a chance of fast indexing your website.