Firefox in future may enable tracking protection (which is a good thing) which will break many ads networks (mainly adsense). And ad blockers are already popular.
What will happen when blogs/sites will stop making money?
I think you can already see it with a lot of those networks. Ads aren't enough to support a lot of them, anyway, once they outgrow the free servers.
* Some write books, and self-advertise those to readers
* Some sell equipment or crafts, etc.
* Some link with IRL events
Though your conversion rates around these sorts of things tends to be lower than ad-clicks or views, the returned gains are much higher. However, bloggers tend to do these things as a network. (Split costs/profits, etc).
The way I see it, blogs, websites and free apps will continue to thrive with:
- Affiliates (already popular)
- Selling collateral products, such as books, merchandise or premium memberships (already popular)
- Native advertisement (on the rise)
- Sponsorship (on the rise)
- Crowdfunding (on the rise)
- Micropayments (in it's early days)
Those monetization strategies can be used singularly or all together, which will also give a good revenue diversification.
The more natural substitute to traditional advertisement is obviously native advertisement and sponsorship. Those two alternatives require a more direct connection between publishers and advertisers/sponsors, leading to a completely different - less scalable, less optimized, but more effective and user friendly - approach to marketing and monetization.
So in conclusion, blogs/sites won't die with the decline of advertisement.
ad networks won't work, but 'internal' networks will thrive. FB exchange, Google Exchange even Twitter, they make a lot of money since they control the entire RTB stack.
* Some write books, and self-advertise those to readers * Some sell equipment or crafts, etc. * Some link with IRL events
Though your conversion rates around these sorts of things tends to be lower than ad-clicks or views, the returned gains are much higher. However, bloggers tend to do these things as a network. (Split costs/profits, etc).