I tested it because I was bored, not because I believed in it
I'd seen other accounts doing the "comment X to get Y" thing and honestly found it kind of annoying. It seemed like a trick. I didn't want my content to feel like a vending machine.
Then I had a post that was doing okay - a free meal planning template I'd made. I had it linked in my bio through Linktree, same as everything else. It got maybe 40 downloads over two weeks from a post with 8,000 views. Fine, I guess.
I reposted the same content three weeks later and this time said "comment PLAN and I'll send it to your DMs." 340 downloads in four days. Same audience, same content, wildly different result.
Why the numbers are so different
I didn't fully understand why until I actually went through the "link in bio" flow myself on my phone. You're watching a video. You want the thing. You have to: close the video, go to the profile, scroll past the grid, tap the bio link, load a Linktree page, find the right link, tap it, wait for the browser.
That's eight steps. Most people drop off somewhere in there - not because they didn't want the thing, but because the friction was enough that they kept scrolling instead.
Commenting one word and getting an immediate DM is two steps. It works because it meets people where they already are.
What I noticed about comment behavior
One thing I didn't expect: a lot of people comment even when they're not sure they want the thing. Just seeing 200 comments saying "PLAN" on a post creates social proof. People comment because others are commenting. Then they get the DM, and some percentage of them actually use it.
It also does something useful for reach. Instagram's algorithm treats a post with 200 comments differently than a post with 5, even if those comments are all the same word. I've had posts pushed significantly further because of comment volume from keyword triggers.
I'm not going to pretend "link in bio" is completely dead - for some content types it still makes sense. But for anything I actually want people to act on? Comments every time now.