I enjoy the phrase because it can have many different meanings. The obvious, of course, is the geographical here, which is the intention of most of these signs. They are making the case that you simply don't know where you are. In many instances, this is probably true and the sign is most helpful.
It can also have other meanings. Yes, you can be here physically, or meta-physically. 'You' can refer to you, or us, or to some other person whom we may never know. It is also refers to 'you' in a certain place in time, right now.
It's great that the sign tells you that you are here, in this spot, at this point in time, but leaves the next location to you to decide. Another reminder that life is a series of choices for us, and that while we may not always know where we are in any given moment, we can adapt, re-orient, and move forward toward the destination of our choice.
It's a good reminder for us. We are always 'here'. Now. Until we're not.
