Both Yahoo & Microsoft did a really bad job for a really long time at simply providing a platform that is comfortable for advertisers to use. I have run ad cam

Both Yahoo & Microsoft did a really bad job for a really long time at simply providing a platform that is comfortable for advertisers to use. I have run ad campaigns on Adwords continuously for 7+ years. Throughout that time I have run ad campaigns on Yahoo, now Microsoft Adcenter, on and off. The last I checked their ad platform was about where Adwords was in 2005. Yahoo had some very reprehensible things on their platform. I had to shut off all of my campaigns because someone at their company was changing what my ads said without my permission. Besides being a legal issue for Yahoo at the time, it put me in a position of unlimited liability. Fortunately, I never witnessed that behavior after Microsoft took over. Yet, Microsoft's platform was just too difficult to get working. That was probably $5 million + in missed advertising revenue from me, just a tiny advertiser. I can only imagine the billions of dollars of revenue Microsoft and Yahoo lost for failing to take seriously the search advertising marketplace.