IAN is used to minimize the chance of an attacker successfully fingerprinting a honeypot. This is accomplished by creating bogus data and history files, alter creation and modification times, add users, patch x number of programs, etc.
"Ian" is the Scottish Gaelic version of John. It is a very common name in much of the English-speaking world. In the UK, Ian was the 19th most common male name, taking account of the whole population (over 300,000 Ians in total).