but deep learning is really a new thing under the sun.
On the contrary, the idea of making deeper nets is nearly as old as ordinary 2-layer neural nets, successful implementations dates back to the late 90's in the form of convolutional neural nets, and they had another burst of popularity in 2006.
Advances in hardware, data availability, heuristics about architecture and training, and large-scale corporate attention have allowed the current burst of rapid progress.
This is both heartening, because the foundations of its success are deep, and tempering, because the limitations that have held it back before could resurface to some degree.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.