If google does switch over to cpa from cpc (if and when that happens) how will blogs monetise? I know for example that weblogs makes huge amount on adsense, but how will they fare if adsense switches to CPA?
I think it depends of blog's topic - if it's general topic, I would not expect much from CPA, but highly specialized blogs, for people who looks for particular information and opinions just before buying product could work better than CPC.
I think thats true. General blogs are a mish-mash of information so are unlikely to work as well. I am on about CPA.