Originally Posted by DamianJ

Don't think people using is instead of are or who's instead of whose are jackson pollock-esque, just stupid or uneducated.

Creativity is great. ee cummings springs to mind as someone who broke rules for a reason. Breaking rules because you're just fucking stupid (you're/your) just makes you look like you either don't care or are stupid. More than likely the latter.

On forums or in personal emails, I can let it slip, except in cases where people are moaning about grammar whilst making a mistake themselves. On 'proper' websites, in marketing copy, in marketing emails etc I think it is inexcusable.