How could one make money from a history/political science/philosophy blog? What kind of ads would work?
1. Adsense 2. Banner Ads 3. Finding Affiliate Products (e.g. Amazon Affiliate Program to sell related Books) 4. Create your Own Product in that niche
Is history/political science/philosophy an "all-in-one" blog? If so, alot of your readers may unsubscribe quickly from your blog if they see alot of content about political science - when they're really there to learn about philosophy.
I don't really like "selling out". I'd rather write stuff like that for fun. However, I can generate far more content (which search engines like) in these subjects, which leads to better rankings, and more traffic. However, a lot of people don't like ads in certain niches, and that can be a turn off. Yes, looking at an "all in one blog".
Banner Ads is a good solution. I think there a lot of authors who would like to promote their books through your blog
Or, it could be that people are used to seeing ads everywhere on the internet by now, so they wouldn't mind seeing them on your blog! In any case, if you have enough traffic to drum up enough ad revenue, I'd recommend Amazon affiliate links (books) as well. Not only do they multiply your chances of earning more (since you get paid for whatever people buy on Amazon through your link) but they also negate the risk of having unrelated subjects in your banner ads.
There's a cool tool out there called LiveChime that allows you to actually target a very niche demographic based on what they are talking about on social media... (Facebook, twitter, google+, etc) you can find people chatting about your subject matter and then reach out to them directly and let them know you're out there. In your example, you could search "history/political science/philosophy" and see who was interested in reading a blog on those subjects. You can check it out on Livechime.com... I hope this helps!
Yeah interesting related books through Amazon was my first though too after reading the OP. You'd probably want entry-level content if going that way though, to attract people just getting into the subject. Experts likely would have read most of the interesting / best-selling books already. Link youngsters & college kids just beginning to explore all these ideas up with influential and popular books on the subject maybe?