I can see from the newbie help that it says that "logging in" and "searching" can trigger this. 

Isn't that a little over-sensitive? 

If I happen to want to respond to a post, or search for something and can clearly see that it isn't there, why do I have to wait another 5 minutes before I can post it?  Similarly if I search, can clearly see that my question has not been asked before, why do I have to wait?

Similarly with posting.  If I'm in many conversations at once, and I have to wait 6 minutes before responses, I'll likely leave and forget to come back...

Same deal with logging in.  That one seems really crazy.  If I'm in the middle of a conversation, haven't logged in yet today, then I have to log in and then wait 6 minutes before I can respond?

I can understand some restrictions to prevent spamming, but it would seem like the newbie only forum + 4 hour wait seems like a pretty good middle ground there.  Maybe 30 or 60 seconds between messages too (like most other forums).  That's enough to stop spammers, and require a little bit of thought on your posts, but 6 minutes is way too long.  I can quite easily compose meaningful and useful responses to threads within 60-90 seconds.  Again, if I'm forced to wait then I'm more likely to go do something else and forget to come back.

If someone is determined to spam, they will work around the restrictions.  Is seems a little overbearing and counterproductive to punish everyone for the actions of only a few.

What's really frustrating is that after getting the "you can't post yet" message, if you wait then it tells you that you've already posted this message.  I have to actually cancel it and start again?