Every time you create post either a new one or you've updated your blog WordPress notifies automatically Update Services by sending a ping, once updated people in the blogosphere can find you most recent posts.

So you don't need to register to other update services, simply put, you want your site moving to the top.

Here the new updated lists:

http://rpc.pingomatic.com

http://api.feedster.com/ping

http://api.moreover.com/RPC2

http://api.moreover.com/ping

http://api.my.yahoo.com/RPC2

http://api.my.yahoo.com/rss/ping

http://blogsearch.google.com/ping/RPC2

http://www.blogdigger.com/RPC2

http://www.blogoole.com/ping/

http://www.blogshares.com/rpc.php

http://www.blogsnow.com/ping

http://www.blogstreet.com/xrbin/xmlrpc.cgi

http://www.blogpeople.net/servlet/weblogUpdates

http://bulkfeeds.net/rpc

http://blogping.unidatum.com/RPC2/

http://bblog.com/ping.php

http://www.newsisfree.com/xmlrpctest.php

http://ping.bitacoras.com

http://ping.blo.gs/

http://ping.bloggers.jp/rpc/

http://ping.feedburner.com

http://ping.syndic8.com/xmlrpc.php

http://ping.weblogalot.com/rpc.php

http://rpc.icerocket.com:10080/

http://rpc.blogrolling.com/pinger/

http://rpc.technorati.com/rpc/ping

http://rpc.weblogs.com/RPC2

http://www.feedsubmitter.com

http://topicexchange.com/RPC2

http://blo.gs/ping.php

http://www.pingerati.net

http://www.pingmyblog.com

http://www.popdex.com/addsite.php

http://geourl.org/ping

http://ipings.com

http://www.weblogues.com/RPC/

http://www.wasalive.com/ping/

http://www.weblogalot.com/ping

http://xping.pubsub.com/ping

Update Ping Services

To use the above-mentioned lists, copy and paste to Settings - Writing - Update Services tab then click save in the WordPress Admin Panel.

Image Credits: http://www.sz-solutions.com