Technology

GovDeals.com in the us and canada

Valid question, I've heard of people just dumpster-diving and getting computers with working components but I'm sure there's places that just wholesale old PC's from schools and businesses for cheap, presumptively after wiping them (one hopes).

Advertising revenue.

Truscape's answer is pretty comprehensive but to recontextualize it: In some places there's functionally zero risk, in fact degrading the US entertainment/media economy might actually be seen as a national benefit. In most western countries it actually is sticking their neck out, though how much depends largely on the location. I think Sweden (or Iceland?) actually had a political party called the Pirate Party which espoused it on some philosophical grounds.

sense of sharing media is that strong?

Essentially yes. Though 'sticking it' to the Disney's of the world (and their regulatory capture of governments) is also motivating.

Well there's a couple factors at play:

• Some disgruntled people who are just frustrated with the current ecosystem of software/media gouging (Piracy of Nintendo and Sony ROMs are the first thing that come to mind, along with things like Adobe product cracks). Slogans would be things like "If buying isn't owning, piracy isn't stealing", and "It's always morally correct to pirate Nintendo games".
• Places that ignore Western/International copyright law and don't seriously prosecute their citizens, who are then able to host databases where anyone can download/stream from, with income from ads and donations (Basically China/Russia, and some countries outside like Brazil)
• Places where the price of purchasing legitimate media is just so insanely high (compared to average income) that having an online distribution network hosted no matter the risk would be the most accessible option (most notably Brazil with their high af import taxes, along with other LATAM nations). This is even seen in places that have no distribution officially period, such as Cuba's "paquete" (Literal HDDs and flash drives being smuggled with foreign data through informal networks)
• "Software Cracker"/"Aaron Swartz" ideologists who believe information should be free and accessible to anyone, no matter what and who pride themselves on releasing protected media not out of financial gain or hatred for the publisher, but for online street cred and to "Democratize" information. This is most notable through shadow libraries like Anna's Archive.

There are probably other cases I have not mentioned, but these are the big ones.

Donations and ads sweeten the pot a lot. Also you don't really need to buy media if someone else already made it available for download, and you don't need to store it if you're uploading to external hosts. So if you're running a video game repacker site, and you get all your games from scene releases, you upload all your files to various external file hosts, and you run ads on your site + inject pay per click links, you could probably turn a profit from your hobby.