You do have a valid point, technically 'encryption' is a method to convert 'plain text' into an unreadable format for unauthorized people i.e. someone without the key to unlock the data back into 'readable' text, therfore its 'two way', and a 'Hash' is one-way, but the definition states that encryption is 'two way' so therefore a 'hash' isnt encryption as (technically) it cannot be undone. But in my mind there both types of encryption algorithms.

As far as i understand both MD5 and SHA-1 have both been deemed 'not as secure as they used to be' because or the numerous types of 'cracking' techniques and SHA-1 was compromised by a research team in China and it’s use has been discontinued by the U.S Government in favor of the SHA-2 family of hashing algorithms.
I think people should start using php's hash function more, as it allows you to hash to more than just MD5 and SHA-1.

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mysql> SELECT * FROM `users` WHERE `users`.`clue` > 0;
Empty set (0.00 sec)