Slang & Internet Culture
ISO
In social media posts, ISO stands for In Search Of. It prefixes a request in buy/sell groups, community pages, and Stories: 'ISO a reliable babysitter', 'ISO two tickets for Friday'. In photography contexts the same letters refer to a camera's light-sensitivity setting, so read it by context.
Why it matters
ISO posts are high-intent requests: someone is actively looking for a product, service, or recommendation. For local businesses, Facebook group ISO threads are effectively free leads, and knowing the convention lets you respond usefully instead of missing the request.
How it is used
Written at the start of a post, all caps, followed by what is wanted. Most common in Facebook Marketplace-style groups, neighborhood pages, and B/S/T (buy/sell/trade) communities. Responses come as comments or DMs; the etiquette is to answer the request, not to pitch unrelated offers.
Frequently asked questions
What does ISO mean on Facebook?
In Search Of. It marks a request post in a group: the poster is looking for an item, service, or recommendation and wants replies from people who can help.
Is ISO the same as the camera setting?
No. The camera ISO measures sensor sensitivity to light; the social media ISO is just an acronym for 'in search of'. Context makes it obvious which is meant.
How should a business respond to ISO posts?
Directly and specifically: answer what was asked, state availability and price if relevant, and move to DMs for details. Group members read generic sales pitches on ISO threads as spam.