First-generation Windows Phone 7 devices should be shaking in their phone-boots. First the HTC Surround disappeared from AT&T's site without a trace, and now the LG Quantum, one of the original three Windows Phone devices for AT&T (the Surround and Samsung Focus being the other two), appears to have been discontinued similarly without fanfare. It's just the latest casualty in AT&T's plan to move toward newer post-7.5 handsets. There are only two pre-Mango devices left in AT&T's lineup, the aforementioned Focus and the HTC HD7S, and we wouldn't be surprised if we're writing their obituaries soon, too: likely successors Samsung Focus S and the HTC Titan are due to hit shelves later this fall.