This is a good idea as long as it has the right filters and controls in place, which I'm confident they will if for no other reason than to whittle down the number of submissions and only having the manpower to go after the very worst. When you watch the dashcam footage on the BBC article, they are examples of shocking driving which anyone would want to see them dealt with as a result.
One really good thing about the initiative is that you CANNOT just upload some footage and be done with it. The person filming must stop using the SD card, put it to one side and keep it for potentially 6 months. They must also provide a witness statement and attend court if required. Furthermore, the person who submits the footage is going to have their OWN driving subject to scrutiny as it must include the whole journey AND anything else that is on the SD card (have they been speeding? Have they themselves driven badly or aggressively?).
In reality, this means that 99% of people will be put off by it, unless it is an example of very bad driving. This is on top of the filters that the police will have put in place to stop people sending in someone making a mistake on a roundabout or such like.
Hopefully, with the above considered, this initiative should focus on the absolute nutters on the road, and not incriminate people who have just made a mistake as we all do when driving.