I think people have different definitions of market timing in their minds - A lot of posters associate it with dancing in and out of the market, which to me isn't intelligent and nothing worthy of praise. However, for others, and I think yoda is one of them, the definition is only on the buy side - "market timing" is fine if you're taking a valuation approach on the buy side, buying when securities reach your estimate of it's intrinsic value, then not selling unless valuations become extremely unhinged in regards to your opportunity cost (say, P/E of 100, or stock yield of 1%, when treasury yields are double that at 2% or more).
However, trying to apply "valuation" to the entire stock market is crazy. There's no possible valuation measure that can account for the differences in all of the different companies/securities in the stock market