Biggest problem is the 10 connection limit, at least if users start opening up more than one tab from your site. That said limitation is listed as "don't care, won't fix" in the bug tracking isn't entirely encouraging either ranking it up there with Bugzilla 915 on the "You know what? Screw developers" scale. (A painfully common attitude amongst browser makers)

There are ways around that limitation, but laughably they involve using websockets or polling at which point...

Kind of a shame it's so hard to make one tab talk to another. You could then just have the first one be the receiver from server-side then have it push to the other tabs.

Broadcast channel or localstorage.change to the rescue? Actually BC might be the answer if there's a way to see if the channel is already open. Of course handling a tab close is then the headache.