Google has recently implemented some advancements in their search engine, other then the popular Florida filter. This new enhancement is a major step in word stemming. Basically, if you do a search on weblog or weblogs it should return the same values. Google never did this before, so this is a brand new add-on.
GoogleGuy said at WMW on December 3rd. "Within the last month or so we've made stemming be more visible, but it's been in a testing mode that's less visible for a while longer. If you like it--great! If you don't like it, you can put a plus sign in front of the word to turn it off, e.g. searching for cert advisory returns great results at #1 and #2 from CERT because we can also match against advisories. If you really only want to match the word "advisory" though, you can search for cert +advisory and then we'll only match that exact word."