[eluser]danmontgomery[/eluser]
The routes are regular expression patterns, so the substitution ($1, $2, etc) only work when you specify groups:
Code:
$route['account/:any'] = "account/my_method";
Will route to my_method() in the account controller, whenever the url matches account/{anything here}.
Code:
$route['account/(:any)'] = "account/my_method/$1";
Will pass $1 to my_method() in the account controller.