The biggest difference, in my view, is that ads are forced upon you, whereas you seek out information yourself. E.g. if you browse a clothing magazine and you s

The biggest difference, in my view, is that ads are forced upon you, whereas you seek out information yourself. E.g. if you browse a clothing magazine and you see a H&M or Zara branded page, that's an ad. But if you're looking through a catalogue of clothes, and there's a section with H&M clothing and a section with Zara clothing, that's information that you explicitly sought out. Another example are billboards and information boards. If it's in large print, so that you see it passing by, it's an ad. But if it's in small print, so you only see it if you intentionally approach the board to see what's new locally, that's information.