[lifthrasiir]

It indicates ownership. If you know C++, ~T in Rust is similar to std::unique_ptr<T> in C++ (ensures that there is only one owner of given value) and @T is similar to std::shared_ptr<T> (ensures that there are one or more owners of given value and the value would be deallocated when the last owner vanishes). But you can't check the correctness of these "smart pointers" in the compile time in C++ while keeping the efficiency; Rust has both the correctness and efficiency (1) by making these important types to built-in constructs.

(1) Still being worked on.