all I have heard is that if you do it you have a better chance of getting shiny. what is it??
If you use the pokeradar in only D/P/Pt and not in B2/W2. If you use the pokeradar and you walk into the shaking grass, catch the same wild Pokemon over and over again. If you keep doing this over a long time there is a possibility that one of the shaking grass will sparkle. This means that the Pokemon in that grass is shining. The longer the chain the higher the chance that the Pokemon will be shining. The chances max out at chain # 40 where there will be a 1/200 chance of the Pokemon being shining instead of 1/8192.
It's using the PokeRadar to catch shiny Pokemon. Source, and also more about it.