A gain train is mostly a Twitter phenomenon, where a domme will post a set of rules, and other dommes will comment according to those rules, hoping to gain followers.
I’m sure you’ve seen these posts. Greeneyed Goddess does a couple of them every week:
The advantage to doing gain trains is the increased follower count. More people see your posts, so you may get more likes and comments, and maybe retweets, by people who wouldn’t otherwise have come across your posts.
The disadvantages are that you’re not building organically, so more followers from gain trains might not equal more subs. Also, this behavior may trigger Twitter’s algorithm, because you’re adding new follows fairly quickly, with minimal previous interaction.
I’ve found that gain trains may be useful early on, but at a certain point, you’ll want to stop doing them, in favor of growing your following more organically.
I did not realize following a lot of people quickly would trigger the algorithm. That makes sense! (Sub here). Apparently retweeting and liking does the same.