Thank you for your feedback and kind words. You see, in addition to what Marks already said (those who post to earn points), there are two types of posts: quality and garbage. If we see users abusing the system by posting very brief responses (usually few words long), we have a rule in place that clearly states:
:: NO SPAMMING FOR POINTS POLICY ::
If a user is found to be spamming all over the forum with useless posts with sole idea to get more points, he/she will more likely end up being banned without warning.
The HD Reward Store serves as an extra complimentary service provided to valued members of this community. We will NOT tolerate putting the quality of this board in the middle as an abuse medium.
In a such a case the user will receive a personalized warning. If behavior continues, we usually ban the user.
However, if a new member posts meaningful messages and actually adds value/knowledge to the thread, then it is not treated the same way. Although if many old threads are being bumped, the user will receive a personalized note suggesting to check the dates of threads before responding.
When it comes to actual thread content - if it doesn't hold value today, it will most likely end up being closed.
In future, we are thinking to implement a hack that will notify a user that is replying to an old thread and suggest opening a new one instead.
We also think that not having a posting limitation would decrease the quality of this board. Many light-minded users who just want to advertise might not want to earn such privilege in the first place, so it keeps them away.
If you can think of any further ways how we can improve HostingDiscussion, please do not hesitate to speak up!
PS: My apologies for the delay in response. I was away for holidays.