well i guess it would boil down on what's the aim of your startup and with that, maybe you can pair your application with any of those available technologies that would best suit your need.

>how does all of this fits in a startup?

It is really helpful to be technically sound.

Here is a scenario of what happens if you are not technically sound:

Have you watched The Social Network? There were guys who had an idea but didn't know how to implement it. So, they asked "another guy" who knew how to implement it to do the job.

That "another guy" stole the idea. :)