Notice how it overrides the content before "deleting" it. This is exactly what SN does, too. Posts and comments are replaced with deleted by author to perform a delete, while the underlying item still "exists" in the database. Glad to see this concept of overriding catching on!

Very similar to wiping a hard drive and instead of just setting all bits to 0, setting them to random bits a certain number of times to help reduce the likelihood of recovery.

This could and should be cross-posted to ~privacy