How many Entrecard contests?

There are so many contest where you can win some ec (entrecard credits). The first ones offered something like 100ec, then I saw200 or 300, but now they are about 500ec for the winner.
Before I continue; I’m not introducing a new contest… at least for now.
As I have thought it seems that ec devalue with time. Well I’m not 100%, all this is very new, but I think that with time the entrecard credits will cost less.
Why? well, making 300ec from dropping your card to others’ blog is not much, I think, but if you do it well and learn where yo have to drop your card you are gonna make that many many users drop their cards to you. And the number increases rapidly.
This is what I mean, these are my statistics:

Well, the first graphic is the number of cards dropped by me in others’ blogs and the other graphic is the number cards dropped by other members in this blog. I drop more than I receive as expected, for now, but while I don’t drop regularly, one day I dropped about 4 times and the next I didn’t drop at all, the cards dropped by others are constant, and this is enough to get here:

Right now I’m the top 6 most popular card, but I’ve being top 4, and this gives me many drops. And as long as entrecard gets more popular and there are more members the ones in the top-anything can get more drops. Ok, no everyone will be in the top but newcomers have many drops too, because there is more people that waits to get that easy 2ec cost advertising.
Maybe the increment in ec earning will stop increasing, and maybe it will be in an average of 600 for active members, but then the prizes of the contests will need to be of some thousands ec.
Anyway I’m having too much fun driving traffic to my blog with entrecard, at first my only traffic was from entrecard, but now I have google visits, cool, entrecard really works.