Lexical Luhn Algorithm
I think with the amount of complaints against erring banks like ICICI and other similar credit card issuing institutions, the message posters should exercise enough caution in that they should avoid posting credit card numbers as blog comments. We can see a significant number of comments in Arjunprabhu's blog where the author has mentioned that he has removed the credit card number posted for security reasons.
I think blog authors should devise something like Luhn's Algorithm and perhaps we can call it as 'Lexical Luhn Algorithm'. If it finds a credit card number, it would automatically mask it as ABCDEFGHIJKLMNOP and CVV numbers should be masked as XYZ. This way we can protect our readers' who are innocent and enter the numbers in comments.
Luhn's Algorithm is very effective in validating credit card numbers at the clientside. However, the actual validity of the same rests with the server since it has to check in the database.
Readers: What do you feel? Share your thoughts.