A lot of companies operating the smaller Airbus aircraft are turning off an engine on the taxi in to stand. The reason behind it is to save fuel. Not much on one flight but add it up and it is a considerable saving.
An A320 can easily start moving under idle power on only one engine when it is taxying in. I have been on the flight deck on such an occasion and the parking brake was released and the idle power from the number one engine was enough to get the plane moving.
I understand it is now standard practice for some 747-400 operators to shut down one of the engines after landing before coming on to stand.