On: Don't build your house on someone else's platform.

[webjoe]

I think Shayan Zadeh (co-founder Zoosk) gave a great presentation on this topic a while ago:

Part 1: http://www.youtube.com/watch?v=ZPLtR38-xVY

Part 2: http://www.youtube.com/watch?v=MbhmvXGQehg

Part 3: http://www.youtube.com/watch?v=MbLpbzWsi4U

TLDR; Leverage platform, take advantage of what you're given, but don't become dependent on it.