I didn't give any explanation because I thought it was easy to figure out: it's the IMDb rating and the IMDb popularity.
I suppose you know the IMDb:
http://www.imdb.com
On the IMDb, each movie has a user rating, with the information of how many persons voted. I determine the popularity from this number of votes.
A movie with less than 5 votes has a popularity of 0%.
A movie with 5 votes has a popularity of 1%.
The movie with the most votes ("The Shawshank Redemption") has a popularity of 100%.
Most movies only have a few dozen or a few hundred votes, while "The Shawshank Redemption" has more than 400,000 votes. Because the number of votes grows exponentially with the popularity, for the popularity to be meaningful, I couldn't use a linear scale. I had to use a logarithmic scale (magnitude).
In a linear scale, you
add to go from 5 to 6.
With the magnitude, you
multiply to go from 5 to 6.
This was a great improvement for Coollector. Now, at first glance when you look at a person's filmography, you know if that person was involved in good or bad movies, popular or obscure movies. I hope you'll like it !