Here’s a survey about emoticons that you can take. I recognised some, but others I had to guess.
I like to see what other linguists are doing, and it’s fun to guess what the work is intended for. I’d say this work is part of sentiment analysis: working out automatically how a writer is feeling about what they’re writing. Or tweeting.
So help a fellow linguist out and take the test. It’s quick, and sort of fun.