Sorry if I am asking a stupid question, I saw some sites giving free submission and ping up to a few k web sites. Once you add in your url, there will be indications of sites submitted and ping ok. But what does it mean actually? Does t mean the directory accepted the site and the ping verified that? But when I tried those links I don't seem to be able to find my site even though the ping is ok. Any clues or explanations deeply appreciated.
The short answer is that it lets a multitude of different services like google aware of your site or new content. Wordpress will do this in a very small way for you and you can expand the number of services that will get notified. You can also over ping these services and you can install a WP plugin called MBP Ping Optimizer which will limit the number of pings in a specified period. Add the plug in and paste the ping list into the box provided and change the number of pings. I usually limit to once per hour. Hope that helps