The poem says that in our life we get to roads. One is travelled by several people, and the other by few ones. This is the point where we have to decide which road is to be selected. While choosing remember that the road that u will Not choose, u can't come back and travel through it.
The message is that the life has 2 paths. One of these we have to choose and our future is based on that. Remember we dont have to choose negative path and if we have choose any path then we cant come back.