Disappearing Neighbors

I am not sure what happened with my next door neighbors. They seem to have moved out slowly, but they left their dog behind and they still have a satellite dish on their roof and some furniture in their backyard. There was a for sale sign on the house until Sunday. Now that's gone and so are the neighbors. I don't know if they were forced to sell to one of these companies who will buy your house for your or if they actually found a buyer who will be moving in. The house was for sale on and off for the past year but never got too many visitors. I didn't see much action lately, so I don't think it was sold to someone who is moving in.