>If your application doesn’t require a high level of user privacy, then you should be able to log into your site as a given user. Odd problems will pop up that only affect one user.<p>when the hell is this ever ok? even for a to-do list app. The closest we will come to this is a screen-sharing session with the customer
Scale all the things: 'Setup a caching layer (Memcached, Redis, Varish)'...if only it was just that easy.<p>Prep for scaling should be something like;<p>1. testing to see when you'll need to
2. monitoring so you know when
3. planning before you reach date / time from #2 how you'll do it
4. implement
5. test you've done #4 properly
6. release
7. repeat the whole process<p>Work out a methodical way that makes sense. "Setup a caching layer" is not that.