Well a couple dozen people have already told you not to worry about XP, so I'm not going to go down that lane...

Here's a more tempered solution, but I doubt that it will happen: What if the current XP formulas were modified to take the age of the node in to consideration. For example, once a node is a week old, multiply the odds of a vote causing an XP change by 0.5. Once a node is a month old, multiply the odds by 0.25, etc...

I really like the way that I can do a search for an old topic and upvote an old node if it turns out to be useful to me, and I wouldn't want that taken away. But I also agree that most of the voting on old nodes is probably not happening for valid reasons.

It isn't that important, really. But if we had a simple solution that didn't represent a major change to things as they are now, I guess that would be good.