Twitter acquired a good team with BackType. Too bad for BackType's customers though. Not the end of the world, but yet another example of the perils (in addition to benefits) of using other company's web services.
I think that goes further than 'a companys web services'.
Every business should be looking at their weaknesses.
If you are using someone else's service at the core of your business, that could go away at any time- you should have a contingency plan. The same for if you source something for manufacturing from another country, or have your factories in another country. What if that country becomes unstable? What will the impact on your business be?
There is nothing wrong with building your business on something that might disappear, you just need to understand that.
