Reputation and karma are more... fun.
Reputation and karma, for the most part, are given on a per post basis. You see a post that really made you think or thought was hiliarous, you give them a rep point. Karma comes into play because reputation wouldn't be as strict as admin 'rep points'. Reputation could be increased by attempts to use alters or reputation circles where you get some friends together to constantly share rep points whenever possible (that would be lame). Karma is meant to balance that out. Perhaps karma could also be given out in a gamefaq's fashion...
The thing about reputation and karma is that it would/should increase when you post more intelligent posts. Those numbers aren't limited. In DT_BK's system, you vote for a member once and that's it. With reputation, you judge a person (by their posts!) at an endless ongoing rate.
Reputation and karma will then play into little ways to affect your sen life. For example, minerals gained by posting would be somewhat random based on character count still, but, otherwise slightly random. Karma and reputation will increase your chances of getting higher numbers in that scale. Let's say, for this post, I'm due 8 minerals. In senv5, it's a bit more, so let's say 12 minerals for this post. The random factor though might be 6 to 12 minerals. Reputation and karma then get their chance to play with the odds, and high numbers in both might increase it to 8 to 13 possible minerals.
Reputation and karma will increase your odds of gaining a mineral by making a shout as well. Yes, 1 mineral
As for changing member groups, karma and reputation would be almost necessary. Spamming the hell out of boards won't make much difference because people have to look at your post and give them points for it. Karma and reputation won't necessarily be 100% needed to advance, but it would help you greatly. It would be possible in my system to get to a regular by posting 5,000 posts in the null forum.
The more people that use this system fairly, the better it will be. Of course, this means that any alters made to simply attempt to give out rep points would be deleted and the offender would probably loose his account completely, at the very least, all his karma/rep. In such a system, I won't fark around with people being queer.
As far as actually giving out rep... it'll be SOMETHING like:
5 possible points to give out in a 4 day span...
Can't give it to the same person in 4 day span...
Can only give it out to posts made in the last 3 days...
You neeed 50 posts in order to give out points...
As far as DT BK's system, I see no need to have some equation to base respect off of.
Overall, karma + rep should appeal to a little fun on sen... nothing as serious as a respect number.