Sadly, this is big news. Under "ARCHIVES" in the top menu bar is a month-by-month breakdown of posts. For now, you'll have to CTRL-click and CMD-click (mac) on the posts for them to open in a separate tab/window so you don't lose your place. Working on a fix for that. Not like there's anything else to do.
The SEARCH function in the right sidebar is the real deal, also.