Can somebody explain this please?

some one removed their entry and site bugged

it's called (unsigned) underflow

Everybody want Natural Selection 2!

There's nothing to explain, you have a slim chance of winning, that's all.

It's a very common bug on Steamgifts. Don't worry, there aren't actually 4,000,000,000+ entries.

Natural Selection 2 giveaway image?
Well you see... It's the viewpoint from inside of an alien's mouth, standing in front of a strange wall of text which says "Natural Selection" with some scratches on it.

Well, some people believe that "Seducing Girls" "can be not that hard". Now, you see, that logically makes sense. After all, if they are seducing girls, as the name indicates, they are probably trying to seduce somebody. In the odd chance that target of such seduction, call this person "the seducee", is you, well, then you have probably up to or more than 45% chance of actually being seduced by that girl. Now, if they are seducing, but you are not the seducee, then your chance drops to up to 32% or more, even if you yourself are a girl. That said, if you are a seducing girl yourself, then you can re-estimate the probability based on your particular choices, in particular if you like the seducing girl yourself, and the chances can go up to 123% or less. Or more, depending on your previous experience and age.

Now, was that so hard?

(Trust me, I am an engineer.)

Steamgifts uses unsigned integers

When something glitches it tries to set it to -1, but because there's no negative sign it just rolls on over to the largest number possible which is some power of 2 because binary

Basically bad programming.

Yes it costs 25 points to enter. unbelievable right?!

Where can I get that steamgifts addon?