Dear Sirs! Here is Geojson.io announced by Mapbox.com

Connectikpeople has observed that, with Geojson.io Mapbox.com is trying to make it easier to draw, change, and publish maps. This means Geojson.io aims to allow users
to collaborate, edit and share geospatial data all through your browser. 

Connectikpeople may recall that, it's an an open source project built with MapBox.js, GitHub's powerful new Gist and GeoJSON features, and an array of microlibraries that power import, export, editing, and lots more.