From reading their blog, it looks like they keep up well with technical changes required by the sites they ping.

Additionally, some services that have disabled their ping url’s now only seem to accept pings coming from pingomatic directly.

I deemed it therefore better from now on to use pingomatic with an additional list of ping services not supported by pingomatic.

Here’s the updated list (just copy and paste this list into Options > Writing > Update Services):

http://rpc.pingomatic.com

Disclaimer: This list is provided “As Is” with no warranties nor guarantees and you should do your own proper research before using it. I am not affiliated with pingomatic nor with any other ping service.