I've written quite a number of graph/visualization UI controls myself over the years (mostly on the desktop) and in the course of doing so, have looked at many

I've written quite a number of graph/visualization UI controls myself over the years (mostly on the desktop) and in the course of doing so, have looked at many 3rd party libraries / widgets. Many of them claim to be able to do 10's of thousands of points / lines / etc; but I'm still wondering, I have yet to see an actual use for it. 25k data points = even at 1024 * 768, a point density so high that the graph is basically a big colored blob. For infoviz (although I don't have a formal background in it), I've always taken the approach of implementing more intelligent data point selection algorithms - better selections of what points to actually display, to maximize the information the user gets out of the graph, rather than trying to push as many data points per frame. Similar to improved LoD algorithms making 3d worlds better when raw pixel throughput in the 3d rendering path can't keep up. Anyway my question is, in what circumstances do you need to render 25k data points per frame / render loop? Aren't there clusters of 10's or 100's of them who end up obscuring each other anyway?