We've also seen how it looks like with Google, with a lot of features that later did become standardized - or obsolete - being implemented in either Chrome, or in their Gears addon (http://gearsblog.blogspot.com/2011/03/stopping-gears.html), which led to application caches, IndexedDB, File API, geolocation, web workers, notifications, etc.

Oh and early on they had URL prefetching, but that led to badly written web interfaces from executing operations that shouldn't happen.