Since the launch of Haswell, Intel has been retiring older processors to make way for the new generation, and to ensure that consumers buy the latest generation of processors. This time around Intel will been retiring twelve Core i5 processors and three Core i7 processors from the 2nd Generation Core processors. The Core i5 processors going into retirement are: the Core i5 2550K, 2500K, 2500, 2500S, 2500T, 2450K, 2400S, 2380P, 2390T, 2310, and the 2405S. The Core i7 processors going into retirement are: the Core i7 2700K, 2600K, and the 2600S. So if you want an Intel processor that can reach very high clock speeds without needing LN2 cooling, now is the time to buy one before the stores run out.
Two Ivy Bridge processors will also retire to make way for some new Haswell processors. The two Ivy Bridge processors are the Core i5 3450 and the Core i5 3450S. They should make way for the Core i5 4670, 4570S, and 4570, as well as the 4430S.
Despite all these chips getting retired, there is no need to be alarmed. This happens all the time, and it is how Intel makes sure you buy the newest processors. And again, why would you not? The new Haswell processors will have a much better iGPU, improved architecture, support for PCI-Express 3.0, and much more.