If you have a Facebook group, awesome! If not, no worries you can still leverage them.

If you have your own group, anytime someone asks a question, feel
free to share a link from your site that answers their question.

This not only drives traffic, but it helps you build a connection with
your visitors. Which means they will be more likely to convert into
customers.

Now you only want to link back to your site when the content benefits people within the group. if it doesn't then don't share the link.

If you don't have a Facebook group, why not join groups within your
niche. Searches for keywords on Facebook and you'll see groups within your industry.

When people have questions, answer them. Help them out. And if you have content related to their question, feel free and link out to your site (assuming it answers their question).

This is a long term strategy and is more about relationship building
than just driving traffic back to your site. Keep in mind this only works if you are joining relevant groups.