I'm also polyamorous, which OKCupid still irritatingly does not include as a relationship status (despite their relative progressiveness on most things). I'm not using "open relationship" because it's not the same thing - I think it would be misleading to suggest that my "relationship" slot is filled. But I have two current partners, so if that bothers you then you shouldn't waste your time on me either.
I'm a fairly introspective and reserved person, and I don't like talking about myself, especially not publicly... so I don't know how much I can put on a public profile. I don't want to be one of those generic "I have no idea what to write here!" people, I just find I can explain myself much better in a personal conversation, or to meet particular prompts/questions that let me go into detail on relevant topics.
I tend to like just listening to other people, learning about them and how they think, rather than saying a lot myself... Until an issue I have a strong opinion on or a topic I'm passionate about comes up, then it's hard to shut me up.