Electa live is an online virtual classroom that can be used for schools, universities, companies and also home school.
It helps you run online presentations, web conference rooms, personal virtual classrooms, online sessions and it also provides you with the chance to create a professional environment to teach live over the Internet.
They used to offer some additional features like not having Prezi's logo on the slides and more free space. However, to have this 'privilege' one had to use an academic email. Seems they are not offering this anymore. Aside from this change, Prezi is wonderful for those who like creating sophisticated and more interesting presentations. I have used it, and I'm pretty satisfied.