Researchers tracked three browsers (MSIE, Firefox, Opera) in 2004 and counted which days they were "known unsafe." Their definition of "known unsafe": a remotely exploitable security vulnerability had been publicly announced and no patch was yet available. MSIE was 98% unsafe. There were only 7 days in 2004 without an unpatched publicly disclosed security hole. Firefox was 15% unsafe. There were 56 days with an unpatched publicly disclosed security hole. 30 of those days were a Mac hole that only affected Mac users. Windows Firefox was 7% unsafe. Opera was 17% unsafe: 65 days. That number is accidentally a little...