Just as I thought, the newly cleaned portion of the carpet was, well, a lot cleaner than the rest of the carpet. So, now my carpet looks like it has some horrible disease. There's just this big streak of light-colored, welty carpet running across the floor. About half-way through the process, my husband came in to see what I was up to, and I asked him which was better, all the black spots or the streak of clean. He said he kind of liked the black spots because that way, whenever he walked into the office, he could pretend he was standing on a hyena. I don't know where he comes up with this stuff.
**Update 10/26/08-I seem to have a fair number of people that land on this post after doing some kind of a search regarding "spots" and "carpet." I can only assume that they are trying to find some good spot-removal techniques. Well, for what it's worth, I used the Just'n Time Spot Remover, which is made by Bar Keeper's Friend, and it seems to have done a pretty good job on the spots themselves. Unfortunately, the clean spots have not dirtied back up as quickly as I thought they would in order to blend in with the rest of the carpet. Maybe I need to sneak our Basset hound into the house more. He can dirty things up pretty fast.