Your replays are yours, so barring catastrophic technical failure, you should always be able to access them (or at least be offered an option to download all of them if somehow we terminate service).
We're all about data here, so we're going ot extract all sorts of details from the replays and try to learn as much as possible from them. Unless marked otherwise, assume that the data will be part of statistics reported publicly.
We intend for this site to be free for public, non-commerical, individual use forever. We might need to charge for some things in the future to cover development and server costs, but hopefully we cover that without making this inaccessible for the community at large.