http://invest2lf43rqx6mommjdb6el3ehbqfx3lbvlv5p53adg2kuqi7zljad.onion/ethereum-org/index28.html
A 'full node' in the Bitcoin network, one that stores and processes the entirety of every block, takes up about 15 GB of disk space in the Bitcoin network as of April 2014, and is growing by over a gigabyte per month. Currently, this is viable for some desktop computers and not phones, and later on in the future only businesses and hobbyists will be able to participate.