I think they mean http://www.taxi.eu/. It's a single app used by large taxi dispatchers all over Europe; in Hamburg, at least HansaTaxi uses it, the largest and IMHO best dispatcher.

As far as I understand it, taxi.eu is an infrastructure service for dispatchers, while MyTaxi is a bit more Uber-like in that it provides a virtual dispatcher for non-affiliated (but still licensed) Taxi drivers.