I've seen it on alot of other forums and it works miracles sometimes. Having a post count shown to the rest of the forumers provokes useless spam from certain forumers and a need to increase their e-peen as much as they can via increasing post count.
It's a simple, but effective (IMO) way to prevent some spam and it also has another perk. Sometimes the voice of people with lower post count is not heard as much ( you can argue that it's not true because maybe it doesn't apply to you, but it does for alot of people ) and this would remove the "welcome 1 post wonder" attitude.