"to opt" is to choose, or to take an option (choice). When you
subscribe or
sign up for an e-mail newsletter, you are said to "opt-in" or choose
voluntarily to receive the mailings.
"Uproar" generally means loud noises, as in mobs shouting, but here it
seems
to be the name of the newsletter. My guess is that "iWin" is a provider
connected with Windows.
Someone else may have signed you up as a prank, or you may have clicked
a
link somewhere that could be interpreted as your willingness to receive
information by e-mail. If you don't want it, send a "reply" message
saying
"unsubscribe."
Best wishes, Helen H. Gordon
