Dropbox founder Drew Houston is stepping down as CEO after 19 years to become executive chairman, replaced by Ashraf Alkarmi, who is SVP and GM of Dropbox Core (Jonathan Vanian/CNBC)

Jonathan Vanian / CNBC: Dropbox founder Drew Houston is stepping down as CEO after 19 years to become executive chairman, replaced by Ashraf Alkarmi, who is SVP and GM of Dropbox Core — Drew Houston founded Dropbox nearly two decades ago out at age 24, eventually becoming a household name in Silicon Valley …