I guess I've just proven #6 on the list of 108 hypermiling tips :
6) Join a fuel economy forum
In the year before joining ecomodder I was using 5.49L/100km (42.8 mpg).
The same 2 month period last year, I was using 5.32L/100km (44.2 mpg).
Since joining ecomodder, I've been using only 4.81L/100km (48.9mpg).
That's a 10.6% improvement in mpg over the same 2 month period in 2009 !