Ok, first off, the tag I used to hide this text inside the "Continue onwards..." link was the <lj-cut> tag. It can be used simply as plain-old <lj-cut>, or you can set the text it pops up with yourself like this: <lj-cut text="this is the text that will show">.
Ok, the next tag is the <lj user> tag. It pops up something like this: ntang. It's pretty simple too: <lj user="username">.
There are other tags but I can't think of them right now. Hmmm. Anyone who can, slap them in the comments and I'll update this periodically. Add it as a memory and you'll always have an up-to-date list of the latest lj tags. :)