Today is the 6th anniversary of my signing up for seti@home. In those 6 years I've managed to process 68892 Work Units, representing 49 years of CPU time and am currently 1673rd in the world.
At one time, mid 2000, I was up at 703rd in the world but I slipped a bit, to the mid 3000's. Since getting my job a year ago and subverting the odd office machine I've climbed back through the ranks. I suspect my climb was accelerated by some users moving over to BOINC.
A year ago I'd done 30000 WU's so more than half my total happened this year. And the result of that 6 years? I have just one signal candidate to my name, listed on a page more than 2 years old!