I’m a moderator in a few groups and I’m obviously a member of many others.
The admin/mods of the groups will truly determine any success to dropping links.
Many mods don’t allow “spam” in the group and if it appears to be spam, they will delete it they see it or when a member of the group clicks “report post”. You must keep in mind, mods want useful activity in the group and members don’t want to see your spam. You’re not adding value.
The one 36K group that I moderate requires approval before any post goes live. We click approve, decline, or ban member. Some days there are dozens that we block.
Some groups are not well moderated and either things slip through or become a spam-fest. Groups flooded with spam often don’t get great engagement or click through because members can either unfollow or leave the group. We all have enough ads on our feeds, we don’t need it in our groups as well.
Starting your own group gives you control and allows you to monetize it. Many of the groups I’m in are monetized by: their own affiliate links, selling products directly, paid membership to a private/closed group, or selling the ability to post ads.
I’m sure others touched on this, but your links need to be relevant and add value to the members.
If someone post “what are the best brake pads for my Honda?” And you’re and auto parts seller/affiliate, you can try and drop a link saying “this site has some great brake pads for Honda. SAVE20 is a coupon code that I found for 20% off and free shipping. Good luck!
www.superbrakepads.com
That will stick better than just joining a group and dropping links.
Be methodical, be relevant, and be useful.
If you can gain traction in a group, reach out to the admin and see if there is an opportunity to advertise/sponsor the group for a fee. Sometimes they want freebies for gifts/giveaways for the members.
We’ve had some big manufacturers give us high dollar items simply for giveaways for members. Those companies don’t even advertise on the group at all. Admins love money or gifts for their members.