Lol please. There's science on both sides. The problem is there is one side which are sensitive little flowers who are scared of words. And despite giving lip-service to how important freedom of speech is they're too dumb to see their actions are against it.
I ran my first propellar ads campaign and must says its shit so far.
My page normally converts between 1-6% (varies on traffic source and audience), so trialled $100 - which at cpc of 12c pays for about 800 clicks.
Not one sale.
The traffic quality is dogshit. That's not to say it cant work...
Haha yeah that's the best one.
But assuming we can't use that is have to say selling - or the online equivalent which is copywriting.
But to be honest, as a businessman, it's so much better to be reasonably good at a group of skills than brilliant in one.