Either, Lumia 1020 is getting much popular and seeing awesome traction or its buyers are really fond of writing reviews. Just two days in release there are nearly 1500 reviews for Lumia 1020 with nearly 500 reviews for each one of the color models. Surprisingly, devices like iPhone 5 have reviews of nearly 700 for each models after so being out for so much time in market. So, don’t know about anything else but seems it will eclipse every other device in number of reviews very soon :).
It is also really awesome to see 100% recommendations and 5 star ratings for the device!!