I have no idea what those strings of HTML code do or mean (and I substituted [ for <), but they messed up my feed for the past couple days.
They got into my feed because I cut and pasted some text from microsoft entourage.
When I decided to figure out what was wrong with my feed, the clue was "did you edit your posts in MS Word?"
I learned a long time ago not to do that.
Now I know to avoid all Microsoft software when it comes to publishing on the web.