Folks, when you use the lj-cut tag, the text="..." part is not going to be visible on the expanded page. Nor will the system insert a paragraph break before the text following the cut, unless you explicitly put it in. So when writing your post, it behooves you to do something like this:
I had a really great weekend, and you can (lj-cut text="read all about it behind this cut.") read about it here.
blah blah blah blah.
blah blah blah.(/lj-cut)
On another topic...
Note that immediately after the cut position, there's some stand-in text to make the sentence end grammatically, and a p-break. Note also that the placement of the end of the cut means that the p-break following that position will get rendered in the short version on aggregate pages. If you're using explicit p tags (along with the "don't auto-format" setting -- I'm actually doing this right now), you generally want to place a cut after a p tag (or after some text at the start of a paragraph), and put the end-cut before an end-p (or before some text at the end of a paragraph).
Here endeth the lesson. :-P