I was just talking with someone last night about how Yahoo is trying to be more like Google (i.e. cache, news, etc.) and Google is trying to be more like Yahoo (i.e. local results). I was kind of exaggerating but if anything Yahoo now made it clear that they want to be Google.
Yahoo! Web Rank is the name that Yahoo! has given to a technical measurement of a particular URL's popularity. If you choose to enable the Yahoo! Web Rank feature on the Yahoo! Companion Toolbar, a toolbar icon will display the Yahoo! Web Rank value of each URL that you visit. The Yahoo! Web Rank values range from 1 to 10. This feature is currently in Beta release.