Keen (of Keen and Graev) has a great post up about what he calls "mudflation" (a combination of the words MUD and inflation). If you've been playing any MMO through the introduction of an expansion, you'll know exactly what he's talking about. That shiny bit of loot you worked for weeks to obtain doesn't look quite so hot when players are grabbing an even better piece from a quick five-minute quest.

Truth be told, "mudflation" isn't actually a bad thing. Change is inherent to MMOs, and it's unavoidable that just as the bar will raise (there will be new heights for players to climb to), so will the minimum rise as well. Mudflation is actually a good thing for the majority of players by definition-- if you consider players as a normal distribution, with a small number of players at the top of the endgame, and a small number of players just entering the endgame, "mudflation" is actually that swell of players in the middle getting their hands on some really new items.

There is a problem, however, with mudflation that I haven't really seen an MMO skillfully deal with yet-- what happens to the content made obsolete? Whenever an expansion comes through town, the old worlds and content get more or less abandoned. While the newest players may still find a little bit of joy in discovering "the old world," they too eventually learn to abandon it for the greener pastures brought with the new content. Mudflation is all well and good for the folks picking up the new shiny items, but it's too bad that MMO makers haven't come up with a better plan for making old content relevant to new players.