Things selling fast, or prices going up fast, don’t necessarily make for a bubble. To me, a necessary condition of a bubble is that valuations are extremely high on a historical basis. We just aren’t there on housing — not even close.
I have been meaning to update the long term valuation charts and will soon when I get some time. But, just extrapolating from last year’s chart, we are probably pretty close to “fair value” (which I define as the median historical price to income or price to rent ratio).