If you were interested, here's a short and nice explanation: http://cimss.ssec.wisc.edu/goes/OCLOFactSheetPDFs/ABIQuickGuide_BaselineCloudTopTemperature.pdf
The Infra+ helps to see how strong the convection is.
@IVO wouldn't it be helpful to have all of the tabs/filters/products described? And not on a forum - on dedicated tootlips or a dedicated help page