The title is a bit sensationalist in my opinion... A slip of 0.3% month over month could be due to a lot of different factors. I'm sure Google is keeping its eye on Bing, but it doesn't seem like a reason to panic. Am I off the mark with this?
"The enemy is retreating the wrong direction!" :-)
The fact that Yahoo grew a bit seems to imply there's more at play, like you said.