I think they have basically an agile approach to not only software development but business as well.
Like almost all development methodologies, I think some of their ideas are pretty valid, unless they aren’t.
For example, some of the things I hear a lot from the sort of XP / Agile development styles are things like:
“Get your app out as soon as possible, even if it isn’t fully debugged or fully complete. Let your users tell you what features need to be added, rather than spending the time guessing what they want”
“2 rules of performance optimization. 1) Don’t. 2) Not yet!”
1) If you get your app out, and you start spending you time getting people to use it, and it sucks, then you have actively made people who had no opinion of your product now have a negative opinion. If you fix the bugs and add features later, they will just remember that they tried it, and it sucked.
2) You can always add performance optimization later, except what about when need to rewrite 2 months of work because you were too lazy to spend an extra 4 hours during the design phase to build in some ability to scale?