Today, I came across an article on password cracking. In the comment section I saw someone had posted (presumably right after they just read about salting) the following reply:

My solution: don't store hashes as a single SHA1 or MD5 result ...
combine it for further obfuscation. A hash is designed to fall into
enemy hands, so don't make it easy to produce rainbow tables.

SAMPLE - All other password weaknesses still apply!

function generateHash($name, $pass)
{
$salt = '';
for($i = 0; $i < strlen($name); $i++) { $salt = $i . $salt . $name . $i; }
return (sha1($salt . $pass) . sha1($pass . $name . $salt));
}

This code is exactly as secure as sha1( $name . $pass );. It does not make it harder to produce rainbow tables, it is security through obscurity.

I come across an example like this almost ever week. Please stop inventing your own hash functions and use a standard salted and iterated key derivation function.