Having a space in your online class for learners to ask questions is an easy way to link online and offline and can be easier for learners who are nervous of asking in class.
If you know you want to gather questions at particular points in the content, an in-page discussion is for you.
However another option that is less-tied to content would be to use a talk channel specifically for questions. One of the advantages here is that you and learners can "subscribe" so you get email updates with new posts.
Using likes is one easy way you could let learners "vote" to see which one should be discussed in class.
Or, if there hasn't been loads of engagement in that channel, but you want to reach all the learners in the class, you might opt for a pulse instead.
Adding a set of tasks into your online course allows...
Learners who might be nervous about asking in class to ask online.
Learners to see that others have the same question as them.
Learners to answer each other's questions.
Learners to vote on which question to focus on.
Use a pulse (live or timed poll) for learners to say what their muddiest point was for a topic you've just finished.
Set up an ask and answer webinar-type session. You could even set one up but have learners lead it.
Support learners to answer their own questions (some ideas described in Faster, smarter feedback and facilitation)
Other articles you might be interested in
Ideas for blended learning - Different strategies for how you might choose to integrate your online and offline learning.
Overview of social tools in iQualify - An overview of the range of features in iQualify that you can use to get learners discussing and sharing.
Faster, smarter feedback and facilitation - Identifying specific feedback touchpoints in the course to give focused feedback.