I doubt this is a factor, but I personally hate it when things I am reading online are interrupted by ads. I sometimes don't read past the first ad, I find it so irritating. Of course, there might be subtler forms of advertising than a big block of highly visual ad copy, which to me (psychologically) signals the actual article is over. Could there be a subtler form of advertising (which might be choosing to pay more for copy without ads).
I doubt this is a factor, but I personally hate it when things I am reading online are interrupted by ads. I sometimes don't read past the first ad, I find it so irritating. Of course, there might be subtler forms of advertising than a big block of highly visual ad copy, which to me (psychologically) signals the actual article is over. Could there be a subtler form of advertising (which might be choosing to pay more for copy without ads).