I have a product with hundreds of thousands of users that I want to monetize with advertisers/sponsors but that isn't compatible with ad networks like Google Adsense. Currently, I've just been cold emailing companies asking if they'd like to advertise on my product but that hasn't been too effective. Are there any other strategies for finding advertisers/sponsors?
I have a mailing list for my website (https://IndieHackers.com). Right after launching, when enthusiasm was at a peak, I included a paragraph in the weekly newsletter saying that I was looking for sponsors (http://i.imgur.com/EknpPux.png). A few companies got back to me, and I worked out deal with two of them. Not sure if this is applicable to you, but it's a data point nonetheless.
