Even if they have the source, they may not have all the build tools anymore.

Or they have the build tools but the wizard that set up the build system back in the day no longer works there.

Or they have the build system archived and documented but it doesn’t run because some license expired, and the tool vender doesn’t sell that version anymore.

In the near future, there will be another possibility - SaaS cloud tools that are impossible to preserve so they are forever lost.

Wasn’t facebook also found to store images that were uploaded but not posted? This is just a resource leak . I can’t believe no one has mentioned this phrase yet. I’m more concerned about DoS attacks that fill up the instance’s storage with unused images. I think the issue of illegal content is being blown out of proportion. As long as it’s removed promptly (I believe the standard is 1 hour) when the mods/admins learn about it, there should be no liabilities. Otherwise every site that allows users to post media would be dead by now.

I’m fine with this. Instances shouldn’t proxy or cache images because it opens instance owners to a lot more liability than text. A client side setting to not load images in comments by default is better.