The first few games to use an exponential XP curve may have copied each other, but by now basic things like this are simply conventional wisdom in game design.

The first few games to use an exponential XP curve may have copied each other, but by now basic things like this are simply conventional wisdom in game design. Here's Diablo II's incremental XP vs. level graph — essentially identical: http://hothardware.com/articleimages/Item1824/D2-XPScale.png http://hothardware.com/articleimages/Item1824/D2-XPScale.png