No, there are several types of legal agreements on the web in this particular case there’s:

• click wrap where the visitor must explicitly agree with terms of service by clicking a button - that’s what you see when you register an account.
• browse wrap where the visitor implicitly agrees with ToS by just browsing the web.

The former is enforcable while the latter is almost impossible to enforce in free western countries because you just can agree with something just by browsing a public space.