Can anyone explain why it is free to use if you link with dynamically, but not statically? (I've seen this point come up a few times in discussions about Qt here on HN.) I know what dynamic and static linking mean, but not clear about the connection to free vs. paid Qt use. Is it something obvious that I'm missing? Only thing I can think of (admit I didn't think a lot about it yet) is that if you use it for free with dynamic linking, deployment is more of an issue, vs. just shipping a self-contained statically linked app.

Thanks in advance.