How popular is Putin really?

RFE/RL's thinks there's as much myth as truth in the subject of Putin's popularity:
Outside observers often marvel at how "popular" Putin is among Russians, but inside the Kremlin they are aware of how thin that popularity is and that troubles them. Even back in the good old days of 2007, the Kremlin tolerated no dissent and went to seemingly ridiculous lengths to hold down opposition from people like former Prime Minister Mikhail Kasyanov and former Deputy Prime Minister Boris Nemtsov, even though they had no chance of attracting significant support.