An important part of the private beta is to determine the scope of this site: i.e. deciding which questions should be asked here, and which should not. While there are a few meta post about what questions would be on-topic, I think this skips a useful tool to determine scope: the closure system.
If you don't know what it means for a question to be 'closed' or 'on hold', please take a look at the help center.
Closure in private betas
While this site is in private beta, any user can vote to close or re-open a question. One reason for this is that any user can help deciding the scope of the site. If you think a question should be closed for any reason, don't be afraid to close the post. If you do, it is helpful to explain in the comments what part of the question should be improved.
Of course, if there is disagreement on whether a question should be closed, then it is good to take the discussion to meta and decide on what to do. But I don't think you should discuss this before, this risks wasting time on discussing hypothetical questions that may never get asked in the first place!
Closure is not a bad thing
While closing a question may sound like saying "we don't want your question, go away", this is not the intended message1. Personally, I see closure as an indication that we should prioritize improving the question before giving an answer. A lot of questions that are closed can be reopened after improving them. Even if the question is closed as off-topic.
For example, questions about particular implementations of algorithms in some language are off-topic on Computer Science. However, it often happens that when someone posts an implementation, their question is actually about the algorithm itself and can be perfectly fine after describing the algorithm in other means.
Don't ask if you can ask, just ask!
Just as you shouldn't be afraid of closing posts, you shouldn't be afraid of getting your post closed, either. If you have a question of which you're not sure whether it would be off-topic, the easiest way to see that is to just post the question! Even if it turns out the question can/should not be answered here, these decisions are important and useful in deciding what the site should look like.
I guess the bottom line is, closure is a useful tool to determine the scope of your site: try to use it for good!
1: Ok, sometimes it is. But usually not on a private beta.