WordPress is an open source platform, licensed under the terms of the General Public License (GPL), which grants users certain rights regarding modification, use and distribution of source code (see,http://www.gnu.org/licenses/
Plugins and Themes are considered by the copyright holders and community as derivitive works of WordPress itself (see http://wordpress.org/about/
Additionally, every plugin author references and acknowledges that their software is licensed under the GPL within their terms and conditions. EffectIO‘s offer is well within the bounds of the GPL license which allows anyone to sell copies and services on top of a GPL program for money (http://www.gnu.org/licenses/
What we are offering here is an automatic update service, for one year (per product) or as long as you are a subscriber, for all the items available in the shop. Download the FREE EffectIO Dashboard and update all items in your WooCommerce shop!