Just to play devil's advocate, let me toss in time of day, as well as other events peculiar to this current October as possible factors...
- World Series finished last night, a particularly exciting series. Giants won in four games. :)
- We have Presidential elections coming up in a week. Rule of thumb I've experienced in several businesses is that business is always down in an election year.
- We are in a worldwide Depression, with armed conflict in many areas.
- Search results are changing... and the search landscape is changing.