You see when some search engines put ads at the beginning of the search results, without separating them, just indicating they're an ad with a little chip? This is what's called native ads. It is ads that is not really separated from content in order to not bring direct rejection from end users. What are the benefits, the cons? Let's take a look. Firstly, almost all native ads is not blocked. It requires either special blocking knowledge or people doesn't take time to block ads that looks so merged with the content. Also, given it is blended with the content, it doesn't give an higher priority over the content, or a lesser one. This means that your ad should be quiet enough and not too much distracting from the content. But it also means that ad is also your content and people can feel angry about this kind of merge. They somehow prefer when it is separate. I can't tell you much about the costs, but this approach is getting popular, what do you think?