I've used italki for 3 months. I like the idea of learning languages online instead of the traditional offline learning. I can flexibly choose the time and the teachers I like.
Although it is not the only one online language platform I have met (just like I have used another alike learning language platform called NativeCamp before), italki has its unique features which attracts me to join. I do love the concept of 'community'! I enjoy sharing my feeling and doing the exercises freely without pressure. You can have interaction with others who are also struggling with learning a language.