The Malaysia Airlines Flight 370 disappeared months ago. There is nothing left to find or they would have found it by now. There is no reason to stop searching for it, but it is very unlikely there is anything left of the plane to emit a signal. At this point it is most likely they will only find the black box.
No, I do not believe the new detected signal is the missing plane. The batteries were only supposed to last for a month so I don't think we should get our hopes up that any new signals could still be the missing plane. I think this newest signal will turn out to be another false alarm.
No, this new signal is not the missing plane, because the Malaysian officials have not been forthcoming with information so far. They have said that the plane is at the bottom of the Indian Ocean, but they do not have any proof to back that up. They just want the media to die down.
I do not believe the newly detected signal is the missing plane. If it is anything related, it will be the black box. The plane more than likely broke up, quite a bit given that we can't find any pieces of it. While the plane is probably widely scattered along the ocean floor, the signal, would only lead to the box, not the entire airplane.