|It probably depends on the terminology being used, 'barrage' is widely used in the media in a very general way. It actually had/has a precise meaning in most English speaking armies, although the US may be different but has rarely used barrages.
A barrage is a succession of linear fires, typically 100 or 200 m apart, and perhaps several km in length and usually engaging more than one line simultaneously. They could be 'standing' or 'moving'. When moving they could be 'creeping' or 'rolling' . The different terms relate to the way in which the barrage moves, in a 'creeping' barrage fire moves one line at a time, 'rolling' means the the guns firing on the forward line lift to a new rear line.
The advantage of a barrage was that individual targets did not have to be identified, the fire just moves forward over everything, a fireplan of 'concentrations' means that each 'concentration' has to be directed at an identified target. Barrages worked well in WW1 (once the problems had been sorted out) and were also used quite extensively in WW2 by the Brits and Russians (and Germans in 1918). They worked because in those wars, particularly WW1 troop density was high with divisional fronts being quite small. As troop density decreased barrages became less and less worthwhile. A barrage could be preparation or neutralisation (suppression in modern terminology). Of course the pre-cursor to the barrage (although the Sovs in the GPW had the resources to do it concurrently) was to win the Counter Battery battle so that the enemy's arty was limited in its ability to either interfere with the attacking troops or to stop the barrage. Of course it doean't really matter whether a fireplan is a barrage or concentrations, timed or on-call, if you don't dominate the enemy's arty you're in trouble. Arty radars are fairly easy meat, modern sound ranging such as HALO is much more difficult to deal with and dealing with UAVs controlling CB fire is a bit of an unknown quantity because the only army that's faced it was the Iraqis last year when they met 1 (UK) Div (who were also using the most modern radars and most modern sound ranging).