Pinging is sort of like telling search engine spider about your site update. Ping services automatically send notifications to the search engines and different blog directories / services that your website has been updated whenever you publish a new post. So that your blog post will get indexed much faster.
By default, WordPress come with just one ping service “rpc.pingomatic.com” in the list. Having a good quality list of ping services will ensure that new articles get found and indexed by search engines as well as bringing traffic from many other sources. The more comprehensive that your WordPress Ping List is, the higher the chances of receiving traffic from those sources.
Warning: Just please be careful when using too many ping sites. Excessive ping list can be harmful for your website. The more your ping list contains links, the more chance your site get banned. So, try to just updated with these fresh ping list of 2013. we highly recommend using the list below.
http://rpc.pingomatic.com/
http://api.nrelate.com/rpcpinghost/
http://blogsearch.google.com/ping/RPC2
http://rpc.pingomatic.com/
http://blogsearch.google.com/ping/RPC2
http://ping.blo.gs/
http://ping.feedburner.com
http://ping.myblog.jp
http://rpc.blogbuzzmachine.com/RPC2
http://rpc.technorati.com/rpc/ping
http://rpc.weblogs.com/RPC2
http://www.blogpeople.net/servlet/weblogUpdates
http://audiorpc.weblogs.com/RPC2
http://ping.fc2.com/
http://ping.myblog.jp/
http://blogs.yandex.ru/
http://ping.blo.gs/
http://rpc.bloggerei.de/
http://www.feedgy.com/
http://blogsearch.google.ae/ping/RPC2
http://blogsearch.google.at/ping/RPC2
http://blogsearch.google.be/ping/RPC2
http://blogsearch.google.bg/ping/RPC2
http://blogsearch.google.ca/ping/RPC2
http://blogsearch.google.ch/ping/RPC2
http://blogsearch.google.cl/ping/RPC2
http://blogsearch.google.co.cr/ping/RPC2
http://blogsearch.google.co.hu/ping/RPC2
http://blogsearch.google.co.id/ping/RPC2
http://blogsearch.google.co.il/ping/RPC2
http://blogsearch.google.co.jp/ping/RPC2
http://blogsearch.google.co.ma/ping/RPC2
http://blogsearch.google.co.nz/ping/RPC2
http://blogsearch.google.co.th/ping/RPC2
http://blogsearch.google.co.uk/ping/RPC2
http://blogsearch.google.co.ve/ping/RPC2
http://blogsearch.google.co.za/ping/RPC2
http://blogsearch.google.com.ar/ping/RPC2
http://blogsearch.google.com.au/ping/RPC2
http://blogsearch.google.com.br/ping/RPC2
http://blogsearch.google.com.co/ping/RPC2
http://blogsearch.google.com.do/ping/RPC2
http://blogsearch.google.com.mx/ping/RPC2
http://blogsearch.google.com.my/ping/RPC2
http://blogsearch.google.com.pe/ping/RPC2
http://blogsearch.google.com.sa/ping/RPC2
http://blogsearch.google.com.sg/ping/RPC2
http://blogsearch.google.com.tr/ping/RPC2
http://blogsearch.google.com.ua/ping/RPC2
http://blogsearch.google.com.uy/ping/RPC2
http://blogsearch.google.com.vn/ping/RPC2
http://blogsearch.google.com/ping/RPC2
http://blogsearch.google.de/ping/RPC2
http://blogsearch.google.es/ping/RPC2
http://blogsearch.google.fi/ping/RPC2
http://blogsearch.google.fr/ping/RPC2
http://blogsearch.google.gr/ping/RPC2
http://blogsearch.google.hr/ping/RPC2
http://blogsearch.google.ie/ping/RPC2
http://blogsearch.google.it/ping/RPC2
http://blogsearch.google.jp/ping/RPC2
http://blogsearch.google.lt/ping/RPC2
http://blogsearch.google.nl/ping/RPC2
http://blogsearch.google.pl/ping/RPC2
http://blogsearch.google.pt/ping/RPC2
http://blogsearch.google.ro/ping/RPC2
http://blogsearch.google.ru/ping/RPC2
http://blogsearch.google.se/ping/RPC2
http://blogsearch.google.sk/ping/RPC2
http://blogsearch.google.us/ping/RPC2
http://ping.blogs.yandex.ru/RPC2
http://ping.kutsulog.net/
http://ping.rss.drecom.jp
http://rpc.bloggerei.de/ping/
http://rpc.odiogo.com/ping/
http://rpc.reader.livedoor.com/ping
http://rpc.weblogs.com/RPC2
http://services.newsgator.com/ngws/xmlrpcping.aspx
http://www.blogpeople.net/servlet/weblogUpdates
http://zhuaxia.com/rpc/server.php
http://1470.net/api/ping
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://bblog.com/ping.php
http://blog.goo.ne.jp/XMLRPC
http://blogdb.jp/xmlrpc
http://blogmatcher.com/u.php
http://bulkfeeds.net/rpc
http://coreblog.org/ping/
http://mod-pubsub.org/kn_apps/blogchatt
http://www.lasermemory.com/lsrpc/
http://ping.amagle.com/
http://ping.bitacoras.com
http://ping.blo.gs/
http://ping.bloggers.jp/rpc/
http://ping.cocolog-nifty.com/xmlrpc
http://ping.blogmura.jp/rpc/
http://ping.exblog.jp/xmlrpc
http://ping.feedburner.com
http://ping.myblog.jp
http://ping.rootblog.com/rpc.php
http://ping.syndic8.com/xmlrpc.php
http://ping.weblogalot.com/rpc.php
http://ping.weblogs.se/
http://pingoat.com/goat/RPC2
http://rcs.datashed.net/RPC2/
http://rpc.blogbuzzmachine.com/RPC2
http://rpc.blogrolling.com/pinger/
http://rpc.icerocket.com:10080/
http://rpc.newsgator.com/
http://rpc.pingomatic.com
http://rpc.technorati.com/rpc/ping
http://rpc.weblogs.com/RPC2
http://topicexchange.com/RPC2
http://trackback.bakeinu.jp/bakeping.php
http://www.a2b.cc/setloc/bp.a2b
http://www.bitacoles.net/ping.php
http://www.blogdigger.com/RPC2
http://www.blogoole.com/ping/
http://www.blogoon.net/ping/
http://www.blogpeople.net/servlet/weblogUpdates
http://www.blogroots.com/tb_populi.blog?id=1
http://www.blogshares.com/rpc.php
http://www.blogsnow.com/ping
http://www.blogstreet.com/xrbin/xmlrpc.cgi
http://www.mod-pubsub.org/kn_apps/blogchatter/ping.php
http://www.newsisfree.com/RPCCloud
http://www.newsisfree.com/xmlrpctest.php
http://www.popdex.com/addsite.php
http://www.snipsnap.org/RPC2
http://www.weblogues.com/RPC/
http://xmlrpc.blogg.de
http://xping.pubsub.com/ping/
To Update this Ping List, Go to WordPress Dashboard >> Settings >> Writing, Scroll down to the bottom of the page and paste the ping list in “update services”. Then hit Save changes to take effect.
However, I use one further precaution, and that is WordPress Ping Optimizer which will automatically stop excessive pings to the services in the list. Do you know your WordPress blog pings unnecessarily every time you edit a post? Think how many times you click on “Save and Continue Editing” or “Save” button. Your blog will ping unnecessarily that many times you click on those buttons. Save your blog from getting tagged as ping spammer by installing this” WordPress Ping Optimizer“ plugin. This plugin is used to limit excessive pinging in a short time , so that your blog wont get banned due to excessive pinging.
For the latest wordpress 3.5 version and above , Ping optimizer plugin is not necessary.