I want to confirm this, like a website is gaining traffic from last week say approx 60k to 85k then Alexa will decrease same week or after some time ?
Its a algorithm of alexa a site of amazon company. You can see the changes on daily basis on alexa. Install the alexa toolbar if you have not installed it.
you can also try an addon , named as e social which shows alexa and google PR at same time Vigrx Plus | best seo company
it updates all the time. If you check the site you will see daily and weekly changes. But the rank you see based on a 3 month trend.
Depends on how many visitors you get, websites which are in the top hundred thousand, their rankings are updated daily, while for others, it might happen on a weekly basis.
Mine is just under 300,000 for 1 month rankings but gets updated quite frequently and the 3 month list is tumbling real fast.