[kijin]

This is not surprising at all. What would the alternative be? The protoplantary disk that became the Solar System contained free hydrogen and free oxygen but no compound thereof? That's sounds unlikely.

Water forms naturally given enough hydrogen and oxygen at a wide range of temperatures. Since hydrogen is everywhere, and since main-sequence stars produce tons of oxygen via fusion, there's probably a lot of water floating around in the universe. When a nebula collapses into a protoplanetary disk, the increased density makes it even more likely that gas molecules will meet one another and form compounds.

[nilkn]

Water is indeed pervasive throughout the universe. Here's a pretty interesting and relevant article from NASA:

http://www.nasa.gov/topics/universe/features/universe2011072...

[scott_s]

The alternative would be that most of the water around now would have formed during or after the stellar collapse that resulted in our solar system.