If you were to ask me... I would say it is more effective in class IF you need to pick up a language fast enough :D Before I explain myself, I would like to define the learning a language a process that one does the translation of ideas into words and vice versa. Why? Well, in class, you learn the language verbally, visually, auditorily and physically simultaneously. I think the combined learning experience gives a different type of linguistic reinforcement as compared to a single track learning experience online. In other words, you learn by interacting with others (not one but many of them, i.e. your classmates) and you are forced to put the process I mentioned above into use over and over again within a short period of time. Most of the online learning experiences are more individual-oriented. You can learn a language at your own pace, minus away the interaction experience. In the case of group learning by video conferencing, although there is interaction experience, it is a delayed one, due to network lag (even a lag of 1 sec matters!). So, learning in class is still more effective than online learning... I think :p