Ok this is really interesting news but oddly enough I personally see this as partially mainstream. That is to say as big as Craigslist is I still think it would take a certain kind of person to use it for cryptocurrency trade. To me it represents one more signal of what is to come. A BTC ETF is even more mainstream IMHO. Beyond that it's when coins other than BTC start getting listed for futures trading, ETF, Craigslist etc that we really are mainstream. Think how many coins are now on the market and the general public still almost refers to Bitcoin exclusively. Thanks for posting!