Yes, but isn't it worth capturing that content, and in doing so, their users? The search engine I am suggesting could easily transition to being the next Twitter. We grab the content, their users perform searches, and then the users migrate when they see that they can not only search every tweet ever made (since we began indexing) but also add to the database directly (kind of like Google having both a search box and an "add your own URL" box on the main page).