Black Friday is both in-store and online. Some people still go out at 4 am and line up to get a special deal, but more and more people do their shopping online. Almost all retailers have in-person Black Friday sales and online specials, while some even have better prices online than in-store.
As already mentioned above, never use unfamiliar websites. Many times, you get an email with a fantastic offer that directs you to a fraudulent website. Either the money is deducted, but nothing is shipped, or the false site is just trying to steal your payment information. Usually, such deals would appear too good to be true!