Brock Lesnar faces WWE Champion John Cena in the main event at WWE SummerSlam Sunday night. As you may be aware, you can sign up for the WWE Network for just $9.99 a month to watch SummerSlam and the rest of WWE’s monthly pay-per-view offerings. The Lesnar-Cena match is expected to launch the run-up to WrestleMania 31, as the storylines of the summer give way. Who will win the clash of the WWE titans? And more importantly for WWE’s bottom line, how many people will take the hint and sign up for the Network?