Re-using an ejected flash drive I tried to properly eject a flash drive by moving it into Trash. It went up in that little puff of smoke. Now when I try to reuse the drive by plugging it back into the computer, it does not show up in my Finder. What gives? (I am running Yosemite.)
It sounds like you might have dragged it out of the Sidebar on your Finder Window. Try this: plug the drive back in, and then hit  Cmd ⌘   Shift ⇧   C   to go to your Computer view. You should see all your connected drives there; just drag the drive you want back to the Sidebar.