For the hop – you need to DL the Alexa Toolbar and then visit all the sites in the hop.  Alexa uses the data from the toolbar to help calculate the ranking.  I have the toolbar on my PC through Google Chrome and on my laptop on Firefox.  I prefer the Firefox toolbar because the ranking is up at the top on the toolbar for every site you go to.  On Chrome, I have to hit the alexa logo on my bar to see what the ranking is.  It is a lot of fun to visit some of my favorite non blog sites and see if my ranking is better! haha.