From the handy graph from the AnF1Blog site, there are some interesting trends emerging regarding which tracks promote overtaking
First is the obvious one that wet races produce more overtaking.
Second is that massive tyre degradation plays havoc as in Canada
The most surprising thing is that the first race in Borerain / Snorerain is actually 5th in the standings for overtaking manoevres.
Unsurprisingly Monaco and Hungary are bottom, but oddly Japan is below Valencia and Barcelona.
Of course this is a very simplistic graph – it doesn’t show whether the overtakes were just Virgin and Lotus overtaking HRT after their pitstops, or Lewis overtaking Alonso for the lead – but it does paint a sad picture when 4 tracks have less than 10 overtakes in the whole race.