My initials are JTS, so my username is a sentence, JTS is Yoda.
Once I was having lunch with a friend. He told me he wanted to run a marathon. I told him how I had done it before, and I started telling him everything about my training. And I mean everything. I would talk for like 10 minutes straight; he would ask a question, and I'd talk for another 10 minutes straight. At the end of lunch he said sincerely but with a chuckle, "Thank you, Master Yoda." It kinda fit because he had no idea I knew so much about it or was even capable of talking that much... just like when Luke didn't know Yoda was Yoda when he first met him. Since I always liked Yoda I kept the name.