Not every site. There is data I would really love to access on Facebook without having to gain specific authorization from the user. It's odd that for most user profiles the most you can extract via the graph API (with no access token) is their name and sex. Whereas I can visit their profile page in the browser, see all sorts of info and latest updates (and not even be friends with them)
Tried scraping Facebook. They have IP blocks and the like.
Do it in JS, client-side with 3 second delays. I have used this to get available data (location, name, status, etc) from the latest 500 available likes of a page I manage
Tried scraping Facebook. They have IP blocks and the like.