AMD has seen incredible success with the Opteron. By far, it has been the chip that has put them on the map for enterprises and small businesses alike. Their early big backers, like HP, are definitely patting themselves on the back when they opted to sell it. In fact, the gains they have had are almost unreal to some, which now shows the Opteron holding about 25% marketshare from servers, up from almost nothing just over a year and a half ago. The article makes a good point regarding how the Opteron has helped shape AMD the past few years:

There's no question that Opteron and Opteron alone is responsible for AMD's inflating shares. The company has gone from essentially a non-entity in the x86 server market to a major player - holding about 25 per cent of the segment. Opteron has completely changed AMD's financial state, giving it a cash cow.
Similar to Sun, their recent innovations have resulted in them considered an almost "must-have" for many datacenters, and the world's biggest chip player has seen massive losses. Can the Xeon recover? While Intel recently climbed back to the top in desktop performance with the Core 2, they may have been looking in the wrong direction. It's suggested they could see themselves soon slip below 60%, and even further from there. Another year from now, will AMD see even more share? We all know it's even shaken mighty Dell - whom for years stubbornly refused to sell AMD anything, and is now offering both AMD servers and desktops.