Fundamental analysis of information forgetting schemes in recursive identification shows that they can be classified into two basic approaches : relative and absolute forgetting. The augmented UD identification (AUDI) algorithm developed by the authors reveals that all the information pertinent to identification and information forgetting is contained in a single matrix called the augmented information matrix (AIM). The tracking ability of the recursive algorithms is determined by the relative weight that is put on to the new information contained in the regressor, compared with the information already contained in the AIM. This relative weight can be easily controlled by the simple diagonal loss function matrix produced by the AUDI method. This simplifies the interpretation of both new and existing information forgetting approaches and also provides helpful guidelines for design.