I find it a bit of a worry that the system will allow you to know who is praising or persecuting you through the PM system. It's a bit like deliberately sending them a PM.
By observing who does or doesn't praise you, a tit-for-tat mentality will develop. A person will feel guilty for not reciprocating, or hurt that another person never notices them.
Whilst, previously, the best way of getting [illegitimate] points was to (1) start a separate account, (2) have an agreement with a co-conspirator, or (3) have a stalker/admirer, the new method will encourage profligate praise in the hope of reciprocation (see Twitter follows), or abject laziness and no praising (which is quite likely how I will deal with the new system).