WordPress Update Services are tools which are used to let other people know you’ve updated your blog.
WordPress automatically updates popular Update Services when you have updated your blog by sending pings each time you create or update a post.
Listed below are Ping Services WordPress uses:
https://rpc.pingomatic.com https://rpc.twingly.com https://api.feedster.com/ping https://api.moreover.com/RPC2 https://api.moreover.com/ping https://www.blogdigger.com/RPC2 https://www.blogshares.com/rpc.php https://www.blogsnow.com/ping https://www.blogstreet.com/xrbin/xmlrpc.cgi https://bulkfeeds.net/rpc https://www.newsisfree.com/xmlrpctest.php http://ping.blo.gs/ http://ping.feedburner.com http://ping.syndic8.com/xmlrpc.php http://ping.weblogalot.com/rpc.php https://rpc.blogrolling.com/pinger/ https://rpc.technorati.com/rpc/ping https://rpc.weblogs.com/RPC2 https://www.feedsubmitter.com https://blo.gs/ping.php https://www.pingerati.net https://www.pingmyblog.com https://geourl.org/ping https://ipings.com https://www.weblogalot.com/ping
Update service URL’s are listed under “Update Services” under Settings-> Writing Settings