Yahoo Groups has some useful groups of which I've been a member for many years. I'd prefer that they'd just move to Majordomo-ish mailing lists but short of th

Yahoo Groups has some useful groups of which I've been a member for many years. I'd prefer that they'd just move to Majordomo-ish mailing lists but short of that they're preferable to Facebook Gruops. There is a mail icon in the top-right of my Yahoo Groups screen which I've never clicked. Hovering over it says 'we're unable to preview your mail'. I'm half-scared of why that is.