How do contextual ads deal with language and geographic location? If reddit were to use only contextual ads does that mean that someone from, say Latvia, will never see ads that are locally relevant to them? I imagine most Latvians on reddit don't hang around the Latvian subreddit and advertising a local Latvian service on r/hairdressing isn't going to work. You also have to consider that if you just assume people's language then you'll end up with a lot of pissed off people, because you keep serving them content in Russian.

In other words: it's all well and good for the Dutch national broadcaster, but what about everyone else that gets an audience from a variety of countries?