In its original form, tropes are storytelling devices meant to convey a concept to an audience. The overwhelming majority of tropes on this site are specifically that: devices that can be recreated by an aspiring author who visits this wiki. Other tropes are about identifying how the audience reacts to an event, and are often an unintended side-effect of the use of a trope. If common enough, there are separate tropes for the same thing from two points of view. Some tropes tend to blur that line where both the characters within the story and the audience react the same way to the use of the trope, which sometimes involve a Lampshade Hanging.
In this wiki you will find the use of the comment "in-universe" by someone saying "This trope was used in-universe when..." and that is where a trope more often thought of as an audience reaction is used within the story. One such use is the Invoked Trope, where the characters actively set up the trope in advance, though that happens more often with storytelling tropes.
For an example, Suspiciously Similar Substitute is more often a fan reaction to a replacement character. The reaction is often "You're mostly the same as the previous character, but you're not the one I remember and love." The series Star Wars: The Clone Wars has an episode where R2D2 is lost in battle and Anakin is given a new (virtually identical) droid. He ends up having the same reaction and attitude as most fans have with a replacement character.
And there is also a distinction between what is used in the story and the reasons it was used in the story. For example, Elliot was transformed with long hair during Grace's birthday party in El Goonish Shive. The in-universe reason was to get Justin, who likes playing with hair, to agree to come. The practical storytelling reason was because he would look just like Ellen otherwise.
Word of advice to prospective writers. Despite what may be often believed, even without a Lampshade, writers should be aware of the tropes they are using and how people will react to it. What separates Good Writing and Bad Writing is how much effort there is put into cleaning up the way tropes are used. Do not neglect the In-universe reasons. Give them a Hand Wave at least. Your readers will not forgive you if you don't.
Also compare Watsonian Versus Doylist.
And here are some tropes that are separated by In-universe and Audience Reaction / Real Life (In that order):
- Anti-Hero and Designated Hero
- Ascended Fanboy and Promoted Fanboy
- Brain Bleach and Squick
- Break the Cutie and The Woobie
- God Guise and Misaimed Fandom
- Famed in Story and Everybody Knows That
- Fetish and Fetish Fuel
- Good Is Not Nice and Jerkass Sue
- Hand Wave and Rule of Cool
- Hello, Nurse! and Memetic Sex God
- Innocent Innuendo and Accidental Innuendo
- Invoked Trope and Intended Audience Reaction
- Miles Gloriosus and Fake Ultimate Hero
- Nice Job Breaking It, Hero and Why Fandom Can't Have Nice Things
- Orcus on His Throne and Designated Villain
- Passing the Torch or Take Up My Sword (depending on whether the character lives) and Changing of the Guard
- Replacement Goldfish and Suspiciously Similar Substitute
- Resignations Not Accepted and Retirony
- Shipper on Deck and Shipping
- Shrouded in Myth and Memetic Badass
- Stylistic Suck and So Bad It's Good
See also In-Universe Marketing, a closely related phenomena.
When writing wiki entries, use "In-universe" (either as plain text or as a link to this page) to mark cases of in-story use of Audience Reactions, that don't have genuine trope equivalents.