Now the problem I have with these sign-up codes is that they aren't always readable. How can you tell the difference between a 1 (the number one), I (the capital letter I), and l (the lower case letter L). Depending on the font your code was printed in you could be in real trouble trying to figure it out. That's not the only letter too. How about O and 0. 5 and S. vv (double v's) and w. 9 and g (a far stretch but could look similar depending on the font), 2 and Z. Now let's say your sign-up code is quite long and you have a few of these letter or numbers in it. How the heck are you supposed to figure it out then?
It just so happens that I tried to enter a sign-up code today and ran across this very issue. I have the 1-I-l character twice and O-0. My sign-up code is "7MIOBlaYjp". So how many combination am I guessing here?
here they all are...
A few years ago I was approached by a toy company to do write an application that generates promo codes. I made sure to take these considerations into account when I wrote it. Plus - it's toys so that means there is a good chance a child is entering the code. You have to make it AS EASY AS POSSIBLE!
The same thing goes for CAPTCHA's.