The only "cost" to starting a Paper.li is a desire for discovery. However we do use the third-party ad service, Google AdSense, to place advertisements on all free papers in order to offset costs.
AdSense is an "interest based advertising service", which means the AdSense ads you see on Paper.li have been determined by:
your geographic location;
what google thinks you are interested in. If you’ve never seen who Google thinks you are, check out their Ads Preferences Manager to find out. Pretty interesting stuff!
the paper content;
cookies. You may have noticed that you are seeing similar ads shown across many websites. Example: if you read an article online about running, a cookie may be used to note your interest in running. As you continue to surf the web, you may see coupons to save money on running shoes. Or if you visit a Paper.li focused on outdoors, sports or health, you may see an advertisement for Nike.
As a reader and internet explorer you do have options that can help tailor which ads are presented to you -or- you can completely "opt out" of internet based advertising. Google's Ads Preferences Manager is one place to begin. Another is through cookie management.
Here's a helpful FAQ that explains interest based advertising.
We also offer a Pro package that allows publishers total control over their advertisements. If you come across a paper that is "ad-free", or has special custom ads or videos, you are viewing a Pro paper!