NB: the faq says there's no size limit.

The recipient can download the file via the podmailing app, or a bittorrent client, or a web browser (once the upload is complete) (more info).
To test this for yourself, try downloading some samples here

Files are relayed by podmailing's servers for 30 days maximum, but: "Thanks to our underlying BitTorrent engine, you can still get a file after it has expired from our servers. It will be downloaded from the sender and the other recipients if they keep sharing it."
NB: when I tried downloading with Transmission, relying only on their server (on a Sunday at 8pm GMT) the download speed was 0 kb/s.

this is a great way to move a giant file to a friend if you cant figure out how to port-forward