Seeing all these failed dupe accounts makes me want to make an 'Evil Overlord's List' for future offenders. I just really hate when people put so much effort into anything with nothing great to show for it. But then I started to think about how I would do it, and since I'm a harmless ENFP, the best I can do is post my plans since this sort of thing requires malicious grudge bearing that I can only sustain for about 15 minutes.
If I were banned from some board somewhere, not this one of course, this is what I'd do and not do:
First, I would plan ahead. I would start my duplicate account early in my career before being banned, especially since you somtimes need certain post counts to get into restricted areas. I would only log onto that account through a proxy, or seperate IP address than my normal logon and never mix accounts/IP addresses up.
The dupe user needs to be picked with your own strengths in mind. I can't say how many times I've seen NT's think the best way to case havok is to start an NF account. Well, sure.. lots of opportunity for trolling there, but you guys just can't do it right. Your caricature of an NF tends to be absolutely ridiculous. It usually is some teenage girl who posts lots and lots of smilies and likes anime. That always sends out a red flag for me.
Personally, I'd probably be an INTP, because I have passed before and I could pull it off. And I would pretty much never talk about personal stuff outside of my Welcome thread. I would initially have some sort of crisis, or profess a curiousity.. followed by a pleading Type Me thread.. resolve that, and then just talk theories from there on out.
Sometimes, you just don't get a chance to think ahead before you are banned and need to start a dupe account post-ban. It's not the end of the world, but if you left the forums on bad terms (duh), people will be looking for you. A huge first sign of a dupe account is skipping the Introduction and Type Me phase all together and making the beeline towards the historically established controversial threads showing all the instincts of a long standing forum veteran, and just happening to know who to tweak and how.
When people start an account on a forum, they tend to care about introductions, or whatever the forum is about, and usually have a specific interest in mind. They also usually spend more than half a second picking a name, and people will try to decipher your name if it just looks like jumbled letters. (Come on, levliws, did you really think that was a good name?) So, *usually* you'll want to do a little better than aol_1985. And, it's best not to go with that cool forum specific name that you noticed nobody had in all your posting experience, like Typologycentral, or taking Marmalade_Sunrise now that it's up for grabs.
So, I figure that if I had an undetected alter-ego, I'd probably get bored and want to do something spectacular. I think I would post an invisible 1px gif, or an innocuous emoticon in each of my posts all pointing to an off-site gif, and then I'd just saturate the forum. And then on d-day, I'd change that picture on the hosted server to something absoultely nasty and then, bam! Chaos! Mwahahaha!