Just as spoken language can be transformed into the written mode, so the written mode can be made to resemble the spoken.
We recently looked in class at Tesco's attempts to address their customers in leaflets, as if they know them and really care for them (sounding, with their desperate "We are changing", like a repentant wife-beater, swearing it won't happen again). L'Oreal too have used the same technique - synthetic personalisation - for years. And now this tweet captures it slightly more rudely:
Writers - copy writers for advertising agencies, especially - know that by capturing a spoken tone in their written words they can present themselves to us in ways that position them as more normal and approachable. The combination of direct address, positive politeness and facework is designed to make us believe they are somehow like us. But they aren't, are they? They're faceless corporations spending big money on trying to relate to potential customers because they want our money.
Even some of the apparent good guys - Lush and Innocent - use synthetic personalisation to create a brand identity that chimes with what they hope will be an ethical consumer who feels that the folksy, colloquial, even slightly quirky tone is really addressing them as an individual.