I partly agree in the sense that if you are using Twitter, Facebook, Yahoo, Google, etc. for login/authentication then you stand a chance of losing users. You can encourage users to setup multiple login mechanisms, but I bet not many people would take the trouble.
However I thought that Facebook apps can also be standalone web apps with some extra work. Also, It seems safe to use web services for things like MongoDB (mongohq.com), CouchDB (cloudant.com, iriscouch.com), RDF (dydra.com), etc. to power backend services because you can always switch to running this stuff yourself. So, data store platform services seem safe enough, assuming that you trust the vendor.
I am not an entrepreneur (just a happy consultant) but if I did want to start my own business I might use the FB platform, but try to allow alternative access to my business.
However I thought that Facebook apps can also be standalone web apps with some extra work. Also, It seems safe to use web services for things like MongoDB (mongohq.com), CouchDB (cloudant.com, iriscouch.com), RDF (dydra.com), etc. to power backend services because you can always switch to running this stuff yourself. So, data store platform services seem safe enough, assuming that you trust the vendor.
I am not an entrepreneur (just a happy consultant) but if I did want to start my own business I might use the FB platform, but try to allow alternative access to my business.