G[od I love porridge! You know, that dish made of rolled ]oat[s. A ]fel[la called out to me on the street recently. “Hello, good sir!” he cried. “Do you like porridge, per]ch[ance?” he enquired, while he had my ]e[a]r[. I replied, “Yeah, it’s ok I guess.”
This had better work, or I’ll look like quite the fool.
]
It works 
In case anyone’s interested, it seems that vBulletin uses an oversimplified algorithm for mouseover previews. Anything between square brackets is assumed to be part of a tag and gets dropped. This includes real tags, vast tracts of text, or a combination of both (the closing bracket of a real tag also closes off pseudo-tags, as demonstrated in Revenant Threshold’s tests).
Oh damn that was funny.* Thank you. Made my night.
…One point for the Welly Kiwi’s!!! Well done Mbossa, made me laugh too!!!
hehehe. Touche`
Any bets as to when the first person will be banned for using this to display a really offensive message? Or when there’ll be a new rule forbidding this? Or when the feature will be turned off entirely?
Thank you, thank you
As well as being a fun thing to do, this trick has a practical upshot. When a spoiler is put near the start of an OP, the preview normally disregards the tags and shows the spoiler. However, if you wrap the text with square brackets, like so…
[Darth Vader is Luke’s sled that only he can see.]
…it will be invisible to the preview.
This trick appears to be a bug rather than a feature, so it probably couldn’t be turned off. However, it may or may not be fixed as part of the upcoming upgrade to the latest vBulletin software. To fix it, the parser for the preview would have to be made to recognise (and disregard) valid tags only, so hopefully they would be able to go a small step further and fix the spoiler thing too.