I recently shut down Google analytics from one of my sites for six days while I worked on ways of speeding the site up. I removed the Analytics code from all pages and removed the site from my portfolio on the webmaster tools site.
I was basicly testing the site systematicly to sniff out possible improvements. Five days ago I re-installed analytics to the site and re-included the site in my portfolio.
Tonight I looked at Alexa stats and find that for the six days the analytics software was off my site Alexa shows zero pageviews. Immediately before and immediately after the Alexa details look somewhat accurate but on the low side (ballpark anyway).
Other tracking means show that the site didn't dip at all during that time. Is Alexa pageview data being generated from Google Analytics? Or possibly from data gathered by the google toolbar which I didn't remove?
ankurjatin, Your Alexa ranking is not as important as you probably think. Since the primary users of the Alexa toolbar are webmasters, you are getting a very skewed sense of your traffic by using it. Your best bet is to check the analytics for your site as well as your positioning in the SERPS, as those are more relevant in getting tangible results.