There are loads of European forums who post keys, the reason we don't is that most of the forums who post keys either are forced to change servers relatively frequently (often losing the entire database), or must use servers closely linked to online businesses or are plagued with popups.
We can use a relatively standard priced server, whereas independant key posting forums pay far more and can get kicked with little prior notice.
The other factor is that why do we need to, when there is no shortage of sites offering key and file downloads.