To be honest, I'm not entirely sure I agree with the Creative Review's definition of 'twee music' (Woody Guthrie? Twee? Really?) but their interview with Dan Stevens, a director at music PR and management company, Darling Department; Parv Thind, sound designer at Wave; and Peter Raeburn, founder and creative director of music production company, Soundtree about the gentle soundtracks to current advertising is still worth a read:
Yes, it does seem like the Balls ad was the first to have that folky, acoustic sound. Actually, the ad featured a combination of image and sound that together blows you away because you’d never seen or heard an advert like it. It’s really powerful and that definitely has a knock-on effect.
People saw that ad and thought, ‘what a great formula’ and when people see a formula that is clearly working it’s easy for them to say ‘let’s do something like that’. That’s the power of advertising! It has the power to start trends (and sell records). Before Balls, there was a trend for finding quirky old tracks from the 1930s that no one had ever heard of. The music that was on PlayStation Mountain is a great example. There was a Wrangler ad with Follow The Yellow Brick Road on there. It’s a trend that’s still ongoing.