It was a classic tit-for-tat. No sooner did the idea that Facebook is challenging Google in search re-emerge than word of Google challenging Facebook's social network dynasty came from none other than Digg co-founder Kevin Rose. Rose tweeted June 26 : Google hasn't responded to my request for more info, but I can tell you now its spokespeople won't comment on what they deem "rumors or speculation." But what could Google Me be? Google already launched Buzz,