I came across a website that is in a low paying niche (youtube/entertainment videos). But for some reason; the site was showing Car Insurance ads. I looked at the source code and this guy had a lot of text in hi source that was talking about 'car insurance' and stuff like that. The trick was that this code was in a CSS div that was being hidden with a 'display:none' property. Now obviously this is not allowed by Google.. am I right??
yes. hiding keywords is frowned upon by google. if your doing it to get high paying keywords,surely it will get you banned.