... Read whats between comment tags <!-- --> and derive its contextual advertising from that. Because I am trying to find a way to may my ads very targetted without being super spammy on the page or doing hidden text.
I don't think the adsense bot can read comment tags but i do know of this technique that could help getting better ads regarding relevancy.
Probably not because try to think what if you made googlebot, would you consider what is between comment tags? I wouldn't.