I think they will try to avoid it as long as possible, and online ad spend is hardly the bottom line panacea it once was anyway. But in the end, money talks. So long as there is an option for paying subscribers to retain the clean UI we now have unchanged, but to open up our writing to (far more) non-paying members and non-members, who do see ads, and we get a share of the revenue from those displayed while they read our stories, I'm not sure it would be too bad.