The global network search at stackexchange.com uses Google search (though it doesn't show that on the homepage).
Since Google has dropped the plus character for indicating required search terms, the operators on regular sites and the global site no longer match.
multi user +vpn +windowshas no hits on Stack Exchange, but does on Super User.
multi user "vpn" "windows"does show results on Stack Exchange.
As a possible workaround for Google's change, is there any chance that SE could replace
"term" before submitting it to Google?
(I'd rather not see SE drop support for the
+ as well...!)