All of the online ad revenue comes from views/impressions, so cutting off a majority of their online customer base does affect the ad revenue. We're probably talking $1-$2 per 1k impressions, but that can add up quickly.
In other words, there's no such thing as a free reader. I read the IndyStar daily, sometimes a few times a day and definitely a few stories a day, so I've probably earned the Star a few bucks.
I'd consider myself a loyal reader, but I can't justify paying $12/month for the Star. I can afford it, but it's a ridiculous price, imo. Here's what I think will happen: This high subscription rate will eliminate 90-95% of the Star's online readers while marginally cannibaliizing some of their print sales. They'll eventually lower the price to draw in more readers but most of the new audience they'll be looking to draw in will be long gone.