Very interesting read, but completely unsurprising.

Reddit post here, followed up with a confirmation from the CEO of Lewt.com (a major D2 item seller).

tl;dr version for these posts; Duping exploits in Diablo 2 are still very common, Blizzard knows about it, ignores it for years without patching, hacks@blizzard.com is useless, Blizzard programmers have been intentionally adding new duping exploits, and the Blizzard employees involved with this are suspected to be profiting significantly from it.

The solution to fixing exploits and hacks is really just posting it on as many different sites as possible, and try to get as many players using the exploit as possible. Destroying an economy and ruining everyones game playing experience is one really good way to finally get Blizzard to act.