Sadly, Vivitek did not ship me the optional Wifi solution for the Q7. Of course my Roku stick works in much the same way, talking to my local Wifi network, but I can only get off or Roku, what they provide. That doesn't happen to include general browsing the web.
Essentially Vivitek offers a very small dongle. It plug into the USB port in the back of the projector, and you configure it to your local wifi the same way you would configure any other wifi device.
That's about all it takes to give you communication with the world. OK, what if you aren't where there's accessible Wifi? Do you have to find the nearest Starbucks? It's easier than that, at least for most people with smartphones, or at the very minimum people with iPhones (I've never owned an android phone). With my iPhone, I can turn my phone into my own, secure Wifi hotspot (once set up), in about 2 seconds).
In other words, I can walk into an office to present to a client with the Qumi Q7, and not have to worry about gaining access to their network. I'd turn on my hotspot, and the Qumi, with the Wifi USB dongle installed, and be ready to search the web, log into my corporate server remotely, and in general, do whatever I need to. In the home entertainment world, same idea. Had the timeshare I visited not had wifi in the room, or if I was paranoid and wanted secure wifi, bingo - out comes the iPhone, and I'm in business.
Because there wasn't one of these dongles included, what I can't tell you, is if you can setup and run, at the same time, both a MHL device (like Roku) and the Wifi via USB. In theory, there's no reason both couldn't be configured, but it's only an educated guess at this point. The local wifi should see the Roku, and the Wifi dongle as simply two different Wifi devices.