The demand to learn English is set to peak at around 2 billion in the coming decade according to David Gaddol, an ELT researcher. This demand cannot be met only by traditional classroom based teaching.
In the other available online avenues, BBC's 'Learning English' website is excellent in terms of the material available in text and audio format with interactive games making it easier to learn English. The British Council's 'Learn English' websites offer a wider range of material from child levels to adult levels. In a new venture the Council is now offering various language learning apps for mobile devices.
For the people who cannot learn English this way and need a teacher, sites like iTalki and Palabea are good avenues where they can use video conferencing to interact with actual teachers who use their own study material and sometimes charge for their online services.
To learn English in a range of simulated 'real life' situations, students may also join virtual school in the 3D world of Second Life where they have virtual schools with teachers as avatars.