I found out something interesting when I’ve gone through my WordPress setting, it seems that the once famous XML-RPC ping sites are either out-of-service or have been taken down.
I once tried to run one of such services to in order to study spam blogs behavior, but it ends up eating too much server resources with too much noise coming from all the submission, I ended the experiment just over one-year.
Probably this is what happening around the world, ping sites gotten shut-down because of being overwhelmed. The remaining option of promoting blog posts is through social status updating site such as Facebook, Twitter and Buzz (also identi.ca!).