One says "Ping weblogs.com", another "Ping KMpings" and the third "Ping TrackBack".
Most blog postings are done from Notes rather than the web so this works fine for me. I post an item - replicate up to my site and then click "Ping weblogs.com" and "Ping KMpings" in quick succession to inform them of my new entry.
Then if my blog posting refers to another weblog that supports trackback I click "Ping TrackBack" - this prompts me for the TrackBack URL of the weblog in question that I can copy and paste into the dialogue box. And I'm done!
I've told the world (well a small but significant part of it) that I have blogged!
A few weeks back I also implemented TrackBack on my site - take a look at any page - you can ping a page/weblog entry on my site to create a TrackBack link or you can click a button at the bottom of each page and fill in a TrackBack form if you don't have the tech smarts to ping me - both methods create a TrackBack link.