another thing could be to think about not giving XP points to people, only because they're logged in, instead to their contributions to PM

This too has probably been done to death, and FWIW, here's why I think the (relatively insignificant) points one may accumulate simply by logging in are perfectly acceptable:

If it encourages just one person to login, that's one more person around who might happen to have an answer to a question asked in the CB.

I've not been here that long, but I've seen many a question answered by people just hanging out, who may have relatively few writeups to their name. I'd prefer to think they're hanging out because of the community, the companionship, and the camaraderie. I like to think that no one is there just trolling for XP.

But so what if they are? To the person they helped, it's just a darned lucky thing they were. Not everyone knows about (or takes the time to) seek out a user's nodes, read them, and upvote them (if they agree) in order to confer XP.

In other words, sometimes a Monk's only "tangible" contribution (CB content being fleeting) might be "being logged in."

So on the chance that someone is just trolling, but they end up helping someone without doing an official writeup, the minimal couple of points they get for "just being logged in" are points well spent.

(In any case, if one desires to know a Monk's "true worth" -- outside of getting to know them by actually reading their writeups or conversing in the CB -- one may simply total the reputation of the user's nodes and subtract that from the experience listed on that Monk's home node. Personally, I have better things to do with my time, like hang out here. :-) )