I'm not into the idea of going back and forth between two sites for searching personally, but if that's how it has to be right now, so be it.
But there are users constantly asking about this, in the newbie forums especially...as such it might generate more spam than it prevents! Related post topics in newbie forums from
the past week:
Forum Search Error
what's up with this site's broken search?
Search restrictions when logged in?
Search feature Useless
Search is throttled for newbies?
So, at the very least, if the error message that appears after repeated search attempts by throttled users could be more informative, perhaps that would stem the tide. Most people don't call a search query a "posting" so it's inherently confusing.
How about: "Sorry, but there is a limit on search frequency for new users. Please wait 6 minutes between searches. This is required to prevent certain kinds of hacking attacks."