MHL is a new technology that allows you to fully mirror your phone onto your tv, not just share pictures and /or home video. It also allows you to display 3D content that is on your phone on your tv. If the tv is a non-3D tv the content will display in regular 2D, and if the tv is a 3D one it displays in 3D. I use the MHL quite a bit and it works on my 2010 Coby and 2008 Samsung. The adapters are a little more common now than when the phone first came out. I have the HTC one and got it through Sprint. At the time my local store gave me 25% off so I paid about 25.00 and they shipped it to my house for free. You can get them cheaper online and at some electronic stores. Just do a search on MHL Adapter.
Oh, I forgot to mention that it has two slots. One is for the HDMI cable and the other is for your power source. You have to have it plugged into an outlet in order for it to work. I would recommend that you get one. I have used it on not only my tv to stream YouTube video but also to play games and have them displayed on the big screen. I also used it on a friend's tv to stream the RedZone channel from my DirecTV app. Hope this helps!