this. There is no world you're living in that people are continously knocking on your door. You're just being a grouchy old man. Glad you have a room in your house dedicated as a library. These handful of people knocking on your door are working way harder for a pittance compared to you.
This response and some of the others are pretty harsh. Sure those people are working hard for little money but a man has the right to want to be undisturbed in his own house...
And I see no one answered the actual question - does the sign actually change anything about the situation from a legal standpoint? I don't know the answer. Obviously no one has the right to come onto your property, and as soon as you ask them to leave they are technically trespassing since they no longer have your permission to be there, right? One way to look at it is that, for a typical home in a neighborhood, it could be assumed that I can walk up to the door and ring the doorbell without being accused of trespassing - again, until I am asked to leave. Does the sign take away that assumption and make it trespassing right away because I am soliciting and the sign effectively tells me that I am not welcome there to do so?