It has been said before that after the public release of Mountain Lion, Lion disappeared from the MAS. The Mac dev center also changed. There used to be a tab for Lion and another one for Mountain Lion, but then we could only get Mountain Lion. Well now we can get Lion again which I am pleased about because I'm dual booting Mountain Lion and Lion. I have installation usb's so it's not such a problem for me. But if I didn't make those usb installers it could have been a problem. I hope Apple continue to support Lion for a while longer. Some peripheral devices still don't have drivers for Mountain Lion (which is why I choose to still dual boot). So the fact that Lion is back in the Mac dev center is a step in the right direction - but it really should also be put back onto the MAS too.