A piece of information accessible over the Internet?

Question

for a certain project it would be very useful to have a sort of variable that is accessible by more than one instance of the same program and from any computer (that is connected to the Internet).

It doesn't have to be much (an integer would be enough) but it should to be possible to read and edit it from anywhere. It should also be accessible 24/24 and of course free.

EDIT: If the answer was in one of those similar articles, I haven't found it (maybe my lack of concentration?). Tell me where if possible.