Even though my Alexa score went from 1,500,000 range to 3,000,000 range........because Chrome doesn't support Alexa toolbar......... during the same 4 months--- my PR went from 3 to 4 --- my SERP went from #5 (non-sponsored) to #2 for "Sacramento weddings" --- and my visits have increased as well as direct inquiries from Google. The best Alexa update? Come out with a Toolbar or Sparky for Chrome!!!
That could go on all day long lol. Alexa is just something nice to look at to see that your websites going in the right direction.
I submitted my site to alexa two days ago or so, it still hasn't started tracking my traffic.. i hope alexa updates soon for me!