I used to have a friend’s password somewhere that used rotation and I’d just have to do a quick bit of maths to figure out the final number. Surely there are bots that are smart enough to automate this: mysuperstrongpass01 -> mysuperstrongpass02, mysuperstrongpass03 etc. [edit: the article alludes to this, but then I most of our comments here and on the link are not very original either!]

Password reuse is probably the worst security flaw nowadays, and a strong but reused password is basically no better than classics like password1 after a depressingly small amount of time/services.