geohot had been preparing the limerain exploit since April, but then he got angry with the iPhone community and decided to withdraw, leaving everyone without a jailbreak solution for iOS 3.1.3. That exploit was used now when Chronic Dev Team wanted to release a jailbreak solution unable to jailbreak for all terminals and I would say that geohot did well by keeping that exploit for now when it was needed more. However, don't think that geohot pulled all the aces out of his sleeve, because today comex a disclosure the fact that geohot still has an unused untethered exploit that will definitely be kept for a future version of iOS.
When this exploit will be used is difficult to estimate, but we know for sure that for the future versions of iOS we are "covered" in terms of the jailbreak and all that remains is to find a decoding solution.
