A WebmasterWorld thread reports a weird MSN pagination bug. Basically, do a search on United Health and then click on the page 2 link. You will notice, if you scroll back down, it will highlight that you are on page 3 and not page two. However, the URL looks correct for page two; &first=10, which denotes that you are starting at result 10. Same thing happens if you click on page 3, from page one, it will make it look like you are on page 4. It doesn't happen with all searches, seems to happen with United Health but not some others.
Forum discussion at WebmasterWorld.
