1) Digital currency 
Flattr is a Sweden-based microdonation provider founded by Peter Sunde and Linus Olsson and launched in March 2010. == History == In March 2010 Flattr launched via an invitation-only basis and then opened to the public on 12 August of the same year. Flattr is a project started by Peter Sunde and Linus Olsson. Users are able to pay a small amount e...