How do you get your posts to be seen?  WordPress has a feature which automatically notifies sites when you publish a new post.  You can specify sites by going to the Options -> Writing admin page, which by default lists http://rpc.pingomatic.com/.

I found an article written by someone who did a little bit of research:  WordPress Pinging Lists : Ping Update Services Smartly.  This article refers to another article written by someone who did even more research:  WordPress Compressed All-Inclusive Ping List.  This second article contains several lists.

I now set my update server list to this set:

http://rpc.pingomatic.com/
http://www.blogpeople.net/servlet/weblogUpdates/
http://bulkfeeds.net/rpc/
http://ping.myblog.jp/
http://ping.bitacoras.com/
http://ping.bloggers.jp/rpc/
http://bblog.com/ping.php