Windows 8 and above support emojis by default:
Emoji - Wikipedia, the free encyclopedia
The biggest problem with emojis is that there isn't a truly set standard, yet. I believe the next version of Unicode (8 I think) will be setting more emoji characters and trying to standardize them across all platforms that support Unicode.
As for video downloading. As long as the video is HTML5 and not Flash, I have found on some HTML5 videos just right clicking and select Save works (but not all the time. It's a bit of hit-n-miss).
One setting I HIGHLY recommend changing in IE is changing the Pop-up settings.
Alt+T, Pop-Up Blocker, Pop-Up Blocker Settings, Blocking Level: High: Block all pop-ups

This will block the "Pop-Under" as well as the Pop-up pages, especially if you visit possible unsavory sites. But it can mess with some legitimate sites, which then I avoid anyway because I HATE Pop-up windows.
As for a "Chrome Store", or "FireFox Add-On" site equivalent for IE. Nope. You just have to Bing around for something. But then you might run into malware. Personally, I'm liking IE for
not to many add on's anymore. The ones that I do have, only come from Microsoft, and some of them I disable because I don't use (Lync, Skype, etc.)