I think a large part of steams success is that they have not messed up... Yet. The other online game marketplaces look at steams success and want their piece of the pie yet forget this critical fact. It takes a long time to trust a company to guard the keys of the digital items you "own". sarcastiquotes because ownership is very weak with these services.
Anecdotal evidence.. myself, It took me 5 years of steam behaving itself before I bought anything on it. I am perhaps not a reference customer. I am a bit paranoid, I really dislike this "half" ownership that online purchases grant you, drm makes me nervous. yet still because steam has remained a stalwart reliable service, it has faded into the background, unobtrusive, and most of my games are on it. I still get a bit sick to my stomach when I think what I will lose when, not if, steam management starts "messing up"
Anecdotal evidence.. myself, It took me 5 years of steam behaving itself before I bought anything on it. I am perhaps not a reference customer. I am a bit paranoid, I really dislike this "half" ownership that online purchases grant you, drm makes me nervous. yet still because steam has remained a stalwart reliable service, it has faded into the background, unobtrusive, and most of my games are on it. I still get a bit sick to my stomach when I think what I will lose when, not if, steam management starts "messing up"