Answer; because you're a pretty awesome person, reader, and some of your followers probably wanted you to follow them back.
I myself became interested in your profile wall because your profile pic looks/is the same as the pic I used for my sansxreader story, and you answered my knock-knock joke, so I assumed you were a good person, maybe even awesome if I do say so myself :3
I hope that answered your question, and have a nice day~
- Elina Violets ^-^