To be honest, I don't know what they use.
That is really part of the question.
I just know that part of the Wordpress blog software (which appears to be all in php) allows you to enter a list of sites to ping and therefore update their indexes.
I think that the ping just gets them to send a bot over to your website to crawl it.
Here is an example from Technorati
After you’re a Technorati member and your blog platform doesn’t already ping Technorati, you can configure your blog software to ping Technorati automatically by entering http://rpc.technorati.com/rpc/ping into your blog’s configuration.
So what I want to do is find out what wordpress actually does with that kind of url.
Whatever it does, I want to do it each time I update my CMS with a new post.
Here is an image which shows the Wordpress interface:
I hope someone can help :)