Tor

Tor routes your traffic through three volunteer-run relays. The entry relay knows your IP but not your destination; the exit relay knows your destination but not your IP; the middle relay separates the two. No single relay, and no single relay operator, holds both halves. This is a structurally different promise from a VPN, which is one party holding everything and pledging not to look.

Tor Browser is half the system

Anonymous routing is useless if the browser identifies you anyway, so Tor Browser standardizes what websites can measure, window dimensions, fonts, time zone, APIs, to make users look alike rather than merely unlogged. Use Tor through Tor Browser (or an integration like Tails or Whonix that inherits this work). Routing a normal browser through the Tor network preserves your fingerprint and defeats the point.

Practical corollary: don't customize Tor Browser. No extensions, no resizing the window, no preference tweaks. Every deviation moves you out of the crowd, and the crowd is the protection.

What Tor is for

• Reading and researching without the visit being attributable to you.
• Publishing or communicating where attribution is the threat.
• Reaching services blocked by your network or country (with bridges where Tor itself is blocked).
• Being one more ordinary user whose traffic makes the crowd bigger for the people whose lives depend on it.

Honest limitations

• Your ISP can see that you use Tor (not what for). In some environments that alone draws attention, the correlation that identified the Harvard bomb-threat sender was exactly this. Bridges obscure Tor use where necessary.
• Exit relays see plaintext for non-HTTPS traffic. HTTPS handles this for nearly all modern sites; onion services avoid exits entirely.
• A global adversary correlating both ends remains Tor's acknowledged design limitation. For most threat models this is academic; for the most extreme ones it is not.
• It's slower. Three hops and volunteer bandwidth. Fine for browsing, bad for video calls.
• Logging in as yourself ends the exercise. Tor hides where a connection came from, not who typed their password into their own account.

Behavior is the weak layer

Tor's engineering is excellent; the historical failures are almost all human. Reusing a username from your real life, mentioning identifying details, uploading a photo with EXIF data, or connecting one time without Tor, each has unmasked people whose network-layer anonymity was flawless. The Darwin Awards section is a museum of these. Tor is a component of anonymity, not a synonym for it; the rest is compartmentalization.

VPN and Tor together?

Mostly no. VPN-over-Tor and Tor-over-VPN each reshuffle which party sees what, usually adding a logging point rather than removing one. The two defensible cases: a VPN can hide the fact of Tor use from a hostile local network (bridges are the more targeted tool), and Tor Browser's own documentation cautions against casual combinations.^[1] If you can't articulate precisely which adversary the combination defeats, use Tor alone.