WordPress MU

Hello I have installed wordpress mu and created one user, my question is on the pinging service. Does MU automatically ping ping o matic or will my bloggers have to do this themselves. Is there a setting that must be checked during the signup process,, I am planning on starting a real estate blogging site where agents can signup and blog

pingomatic will ping on every new entry, not on modification, only u have to working pinging sites URLS

use "Smart Update Pinger"
do not make urls too long, as wp take urls from header, give ur own short post slug.

It's built in, there is no settings page, it's not needed. It pings the big places, which in turn ping everywhere else.

You're covered. Quite well.

you said word press MU will automatically ping to ping o matic, how often does this happen, where is the code in wordpress that sends the ping, reason I ask is I have created a normal user under wordpress mu I created a blog and published it to the site. I have used ping o matic before and I know the site will let you know if you already sent a ping within the last few minutes, right after I submitted my blog post I went to ping o matic and it pinged the site and I never got the message wordpress sent the ping already, call me parinoid but I want to tell my site users their blogs will ping automatically so I want to be sure in fact it is