The signs were erected without any consultation, and totally go against what another arm of the council's aiming to do (see
http://www.edinburghcorepaths.org/). Additionally there are still plenty of other signs which give the impression that cycling is ok on the Prom (which to be specific it is on half of it).
The council should be wholeheartedly promoting cycling, including cycling on Portobello Promenade. Especially with all the local road works and the state of Portobello High Street - this "car park" is very dangerous for cycling along (especially the narrow section East of the crossroads).
As someone who cycles daily along the Prom I acknowledge that there are irresponsible cyclists - please challenge them, as I do.
(and likewise cut any of those bloody extendible dog leads on sight)