COBE then has told us what the large scale ripples in the background radiation temperature look like. However there is much to be gained by examining the fine details of the ripples.
Recall that on the large scales, the temperature ripples reflected the primordial ripples themselves. That is because on scales that are larger than the horizon there hasn't been enough time for matter to collect in the valleys and the process of structure formation to start.
When we look at smaller scales than the horizon, we see the process of structure formation at work.
The goal of the current generation of experiments is to understand this process in detail by looking at the small scale ripples in the background radiation temperature.
