I wonder why NetBeans 6.9 is still in Software Center and is not replaced by 7.0?
I mean, the new Firefox package is published within a few hours after release, why is the NetBeans package not updated yet?
Once Ubuntu is released only security fixes or fixes to major flaws are published in the stable release. See here for the policy:
Certain software, like the Firefox can be granted exceptions based on special circumstances, but generally speaking if you want a new version of something you'll have to find a PPA for it, see if it has been backported, or build it yourself.