I regularly use it to check if 2 files that outwardly look the same (same size etc.) are actually the same. I’ll also use it (or to be more accurate, SHA1, the same as the hint above. Just substitute SHA1 for MD5 in the openssl command) as a quick and easy way to verify to people that attachments I’m eMailing them have not been tampered with. It’s the same basic theory as using a digital signature.

Then you have http://support.apple.com/kb/DL930 and the like. Yep, Apple themselves use SHA1 (which is really just a ‘more accurate’ version of MD5 (yes, I KNOW how wrong that comment actually is!) to verify the contents of updates to the OS.

It’s also used by online retailers and things like the Fink package manager. I could go on but I realise quite how boring I can be

So no, not just torrents.