I often get moderation points - but there are not
articles I care/understand enough to moderate it.
What's happen even more often, I find a brilliant
comment I want to mod up - but have no points to do so.
I'm not sure whether it is good idea but here it goes
1. Add new type of non-expirable moderation points.
2. Allow to convert (e.g.) 5 normal moderation points
to 1 non-expirable point.
3. Limit number of non-expirable moderation points to