TWiT has and will continue to turn down advertisers. Why? Because Leo and I do not believe in their products/services OR their products/services do not fit our audience OR we have current advertising partners with similar or the same products/services.
Content drives TWiT, not money. Money allows us to hire exceptional hosts, build sets, improve our website and push our network out to every possible platform available but sales is not our number one focus. I actually drive my sales team crazy because I say no more often than I say yes to new advertisers.
TWiT has been selective about advertisers since it's very first netcast. Leo did not want to consider advertisers for TWiT and wanted to create content and have it solely supported by audience contributions. When Leo decided to allow minimal advertisers on his network he was selective from day one. Why? Because he only wants to consider advertisers who his audience would be passionate about and because he did not want to annoy them with too many ads.
My best advice when considering ads on your network is to make sure it makes sense for your audience. If not, walk away and find another way to make money. Put your content first and serve your audience first. Money will follow.