@bc22:
Is that because each torrent individually needs to communicate with the site server every 30 minutes to update stats and connections?
Exactly.
Every active torrent has to talk to the tracker every 30 minutes, regardless of size.
If you have a 10gb folder of 50 videos in a single torrent, your client and the tracker only need to talk to each other once every 30 minutes.
If you have 50 separate torrents for that folder, your client and the tracker have to talk to each other 50 times every 30 minutes.
On the tracker side, every torrent is deemed "active" waiting for member clients to contact it.