It shows an up-to-date mobbels ranking chart based on the rarity/ availability of each mobbel.
Rare mobbles have higher ranks (100 : not found or unavailable),whereas common mobbles have lower values.
When you're into mobbles trading and exchanging, this gives you agood idea of which mobbles are worth being traded.
The chart is updated every 2 or 3 days at least (no update of theapp necessary), pictures point to the Mobblepedia.