Ask HN: Where can I find discussions on technical architectures?

For example, if I want to just read people's comments on trade offs or a place where I can go to ask for architecture help for creating an application

… If you’re interested in building mobile apps.

There was the time my coworkers went to the Semantic Technology Conference in San Francisco when the WWDC conference was on and some of those people saw us in a bar and thought we were kindred souls and I said, “We’re not building apps, we’re building Skynet.”