Can somebody who has/understands how Mobile Hotspots work help me? I have put money away for the next generation iPhone and I am getting a Retina MacBook Pro in March. I go to A LOT of places that have SUCKY wifi and I want to know what the hell a Mobile Hotspot is and how it works. I have a grandfathered unlimited data plan from AT&T. What am I supposed to buy? Is it a freaking device or an add-on? Will it hurt my plan?