Co- founder of Square Jim McKelvey is launching Invisibly, a much-anticipated micropayment ad platform that will offering publishers a path beyond the subscriber/non-subscriber model. Invisibly will offer viewers the monthly subscriber option, as well as payment per article, day passes, week passes, or the publisher can pop up an Invisibly-served video ad. Watch the ad, answer a few questions, and you get access to the site for a metered amount of time. McKelvey has recruited The Atlantic, The Motley Fool, and Warner Brothers test Invisibly.

Read the Nieman Lab's introduction of Invisibly.