I know many webmasters who daily track Alexa for detailed site status on the internet, and have often been termed Alexaholics. Alexaholic blends Alexa website traffic graphs with a lightweight ajax-enhanced interface.
And what does it mainly do? It allows Webmasters, SEO/SEM specialists, and domain owners to compare and measure website statistics for up to five domains at once, switch traffic chart types and ranges without page loads, and generate report pages that are easily bookmarked and shared.
To test it out, I tried this service for my site and got a great Alexaholic chart for Quick Online Tips. Considering I started this blog on 15 March, their data seems very consistent. I know you will like me to compare Slashdot vs Digg, or maybe Google vs. Yahoo vs. MSN.
Update: Alexaholic was later sued by Alexa and had to discontinue use of the service. A modified service is now available as Statsaholic, which compares traffic charts of upto 3 websites and compares there Compete and Quantcast traffic ranks and charts.