Do hashtags work on Facebook? Apparently!
While not used to the extent as they are in Instagram, they have three keys uses on Facebook:
Using Hashtags on Facebook for Search
We use the search function all the time. We look for a person to connect with, a company to tag...we may (or may not) have used it to see what a friend's ex is up to.
While we usually use full names, you can also search for a hashtag. We searched #GivingTuesday (it's coming up in a couple of weeks) and found posts from several different pages. So, clearly it's a thing.
There are arguments to use both trending hashtags or niche hashtags; one gets a wide reach, the other gets a specific reach. It depends on what you're after.
Something to note: while lots of people love to go hashtag crazy on Instagram, you should keep it to two or three on Facebook.
Bonus: If you use hashtags on your reels, they become clickable - and take you a search page with results from that hashtag.
Using Hashtags on Facebook for Brand Consistency
If you use the hashtag on one platform, you can continue to use it here. Since you're being sparing with hashtags, one can be YOUR brand name - you're doing that already on Instagram, right? - and the others can be related to the trend/topic you're aligning with.
Something to note: try to use them in the body of your copy, not underneath
Using Hashtags on Facebook for Community Building
If you have a hashtag related to your company or product (eg your company name) it makes you findable. If you post in various groups, using your hashtag (appropriately!) in those posts helps people recognize you. If other people start using your hashtag, you can search for user generated content, then share it!
As Facebook groups continue to rise in popularity, admins can use these hashtags to group content together in the group for members to find.
Something to note: just because the hashtag exists doesn't make it USED. You need to be consistent in the use and engage using it to get it seen and noticed.
In the end, hashtags do still serve a purpose on Facebook. It's worth spending some time investigating hashtags meaningful to your brand on the platform and deciding which ones you could use in various contexts.