I think I may be the only Less Wrong member young enough not to have an answer to that question.
There is no reason that should stop you. Most people, when they are answering such questions, tend to give answers that are only loosely correlated with what they in practice end up seeking. You can make up random stuff with the rest of us!
Open to anyone, single or otherwise. What do you look for in a relationship?
A few questions to narrow down the responses:
1: What traits are most important to you in a prospective partner?
2: What kind of role would you want your partner(s) to play in your life?
3: How much time would you spend together, ideally?
4: How important is it to you that you share similar tastes?
5: How important is it that you be ideologically similar?
6: What, if anything, are your dealbreakers?