Anime and Manga Stack Exchange is one of a number of Stack Exchange Websites like Stack Overflow and Arqade. Being a Q&A Site you can always expect good quality answers backed up with facts, logic and some speculation based from observations.
So if there is a question about an anime series that’s been bugging you like how Nanoha’s Starlight Breaker works or why does Madara wear Samurai Armour despite being a Ninja then this is the place to go. Or you can just answer some of the unanswered questions or provide a better one to one that as been answered.
Keep in mind it’s not a forum and some questions will be closed if they are off-topic (ie. “when is Code Geass R3 coming out?”) but so long as you read the tour page carefully and look at other questions/answers to see how things are done you’ll be fine