When does recession become depression, technically?
There is no technical definition of depression, AFAIK. 'Depression' is merely what people used to call a recession -- if you graph GDP growth over time and it goes V-shaped or U-shaped or L-shaped, it looks like a 'depression' of growth. Nowadays I guess people use the term to mean a more severe recession, for instance a long-term stagnant, L-shaped recession like Japan experienced in the 1990s.
There are similarities between now and the Great Depression, for instance: a severe stock market crash, rapid asset deflation, banking collapse, etc. But obviously we're a lot more developed and have all sorts of safety nets -- people aren't going to be living on the train tracks and eating three day old rat for tea just yet.
There's a kind of self-fulfilling prophecy aspect to panics -- like inflation, if you and everyone else expect it, give press-conferences about it, write op-eds demanding action, it will come. And maybe some of Wall Street's princes have fallen on their swords, but most banks seem to have done ok out of holding a gun to the heads of governments around the world.