In one way, that's the beauty of our community. It's very soft and blurry on the edges, which my UX-me loves and my programmer-me hates. Community members can get away with a well-formulated, slightly off-topic question, just because it's interesting. We lose ourselves in interesting things, rather than determining if its on- or off-topic.
Some say this is bad. Others say it's good. But the majority doesn't really care.
Every action a user performs has a property named User Experience. This is the core of the community. The further away from that core you get, the more likely it should be rated off-topic. Career, Why did X design Y, History, Graphical Representation, and Implementation are in that blurry zone where questions can be either on-topic or off-topic.
Personally I think it's good, and I keep coming back to the blog post Good Subjective, Bad Subjective. It is very close to the issues we face here.