I doubt this is the case. If you're working on even a medium sized team, you'll see this level of data, whether it's internal server logs, publicly-sourced data, or a variety of other applications. Almost by definition, any company that runs a cluster is probably dealing with TBs of data (otherwise they could probably run it on one machine). I don't know the percentage of developers that deal with this, but I do know that it's pretty common.