I saw this code <link rel="pingback" href="http://www.xxx.domain.com/xmlrpc.php> in the source code on every page of a domain. I'm just curious what this does exactly?
Link specifies a relationship between this page and the one specified in the href attribute. Not sure how a lot of browsers render this information, but that's what the normal meaning of it is. The rel="pingback" attribute is a name that identifies this link, usually used to give some idea of the point of it. May have something to do with backlinks. What blog software was this site running?
The site was running wordpress. What exactly does it do? Does it mean that everytime someone visits that html page, that html page will send a ping to all the aggregators, eg pingoat, weblogs, yahoo, etc?
It's used to notify a blog if another blog links to them to write something. For example, if I write an article, and you link to it on your blog, your blog software will check the linked article for a <link rel="pingback" ...> tag in the page's header. If found, it will call the url specified, most often an xmlrpc link, to tell my blog you linked to me. Some authors like to know it, and it adds to the community because those links are then shown near the article comments.