This post expands a 66-second video I recorded on September 10, 2026 and published on September 17. It's embedded below.
Social media post descriptions for SEO are worth writing; descriptions for virality are not. A Reel goes viral because of the video, not the caption. But Instagram Reels, YouTube Shorts, TikToks and LinkedIn posts are all indexed by Google now, and AI models pull from that index. The description is how you get found there.
- Descriptions don't decide reach. If a post is going to go viral, it will, with the best-written description or none at all.
- Google indexes social posts now. Since July 10, 2025, public Instagram professional accounts are indexed by default. Shorts, TikToks and public LinkedIn posts already were.
- A social platform shows up in Google's top 10 for 50.3% of queries (SE Ranking, 63,987 sites, 2025). Your description is the text Google reads to decide if that's you.
- AI models read the same text. If someone asks ChatGPT about your industry, a properly described post has a far better shot at being referenced than one with no description.
- Write for the searcher, not the algorithm. Keyword stuffing measured a 9% drop in AI visibility in the Princeton GEO benchmark. One clear question, one clear answer, your name and city.
Watch it on YouTube · Instagram · LinkedIn · X
Do post descriptions help you go viral?
No. If your post is meant to go viral, it will, whether it has the best-written description or no description at all. Distribution on Reels, Shorts and TikTok is decided by how people react to the video itself: whether they stop, how long they watch, whether they send it to someone. The description gets read after the scroll has already stopped, so it can't be the thing that stops it.
Instagram says the same about the part of the caption people obsess over most. When it capped hashtags at five per post in December 2025, it said fewer, more targeted hashtags "can improve both your content's performance and people's experience", and framed hashtags as a categorization and search signal, not a reach lever.
So if you're rewriting a caption for the fourth time hoping it tips a Reel over, stop. Spend that time on the hook of the next video.
Are Instagram Reels, YouTube Shorts, TikToks and LinkedIn posts indexed by Google?
Yes, all four. This is the part most people don't know about, and it's the actual reason to write descriptions.
Instagram was the last holdout. Starting July 10, 2025, public content from Instagram professional accounts can appear in Google and Bing results. That covers Business and Creator accounts for users over 18, and the indexable content includes photos, videos, Reels, carousels, captions and alt text. The setting (Settings, Privacy, "Allow public photos and videos to appear in search engine results") is on by default. Personal and private accounts are excluded.
The other three were already there. Every YouTube Short has a watch page Google indexes. Public TikTok pages have been crawlable for years. Public LinkedIn posts get indexed too, and the first line of the post seeds the page title.
How much does it matter? SE Ranking looked at 63,987 sites between January and August 2025 and found at least one social platform in Google's top 10 organic results for 50.3% of queries. Reddit and YouTube take most of that share, but the point stands: social posts are web pages now, and Google ranks them like web pages.
Which means the description is the page. Google reads the caption, the alt text, your account name and the location tag. There's no evidence it reads what you said out loud. If your industry term only exists in the audio, it doesn't exist for Google.
Do post descriptions help you get referenced by ChatGPT and AI Overviews?
Yes, and I'm actually more bullish on this than on the Google traffic. If someone is looking up your industry on ChatGPT, you have way better chances of being referenced if your posts are properly described than if they aren't. AI answer engines don't have a secret index. They pull from the same web Google crawls, and indexed text with a clear question and a clear answer in it is what they quote.
Two honest caveats from the data. Otterly's 2026 study of YouTube citations across AI engines found long-form videos get 94% of the citations and Shorts get 5.7%. So if AI citations are the main goal, a chaptered long video beats a Short. But in the same study, description length was the strongest metadata correlate with being cited (r ≈ 0.31), while views, likes and subscriber counts sat near zero. Small accounts with good descriptions get cited. Popular accounts with empty ones don't.
The second caveat is how you write it. The Princeton GEO benchmark tested optimization tactics across 10,000 queries and measured keyword stuffing at a 9% drop in generative-engine visibility, while adding quotable statements and statistics lifted visibility by up to 40%. The description that works for AI is the one that reads like a normal person answering a question, ideally with a real number in it.
How do you write a social media post description for SEO?
Say you're a tax lawyer, or a dentist, or whatever. You want the description to reference your industry and the terms related to it, as much as you can, as long as it stays tied to what the post is actually about. Here's the shape I use:
- First line: the question the post answers, in the words a customer would type. Not "Smile makeover ✨" but "Does Invisalign work for adults?"
- Second line: one declarative answer. If you have a real number, it goes here (a price range, a timeframe, a case count). This is the sentence an AI engine lifts.
- Name the entity. Your name, your practice, your city, the exact service, spelled out in words. Hashtags don't create entity mentions; words do.
- Two to four short lines of context from the video itself. Stay inside what the video says. A caption describing something the video doesn't cover is a mismatch, not a keyword win.
- Up to five hashtags at the end, after the prose, so they don't become the snippet. Five is the hard cap on Instagram now anyway.
Dentist version, before: "New smile, who dis 😁 #dentist #invisalign #smile #lisbon #teeth"
After: "Does Invisalign work for adults? Yes. At our practice in Lisbon most adult cases finish within (your real range) months, and the only thing patients complain about is the first few days of each new tray. Dr. Silva, cosmetic dentist, Lisbon. Full breakdown in the video. #invisalign #dentistlisbon #adultorthodontics"
The same description travels across platforms with light edits: it's the title and description on Shorts, the caption on TikTok and Instagram, and the first lines of a LinkedIn post. If you're already reposting the same video on every platform (you should be), the description goes with it.
Can you automate SEO descriptions with AI?
Yes, and this is the part I actually did. It sounds more complicated than it is, so I put together a skill (a prompt file you hand to ChatGPT or whichever model you use) that writes SEO-optimized descriptions for social media posts from either the video transcript or the text of the post. It follows the shape above: question first, one-line answer, entity names, hashtags capped. You paste a transcript, you get the description.
Descriptions are one of the easiest places to hand work to AI because the input already exists. The transcript is sitting there the moment the video is cut. Editing itself is a harder problem, and I've written separately about how close AI is to editing videos like a human editor, but metadata is a solved one.
In the video I ask people to comment "skill" and I send it over. On the blog you can skip that step: download the SEO captions skill here. It's free, and the page walks you through installing it.
Who this is for (and who it isn't for)
This is for anyone whose customers search before they buy: dentists, tax lawyers, accountants, consultants, agencies. It's for creators posting educational content, where every post answers a question someone types. And it's especially for high-ticket services, where one found post can start a sales conversation. That's the whole premise of treating content as a sales conversation at scale.
It isn't for accounts posting pure entertainment or trend audio, because nobody searches for that topic. It isn't for personal accounts, which aren't indexed at all. And it isn't a rescue plan for a bad video. A perfect description on a post nobody watches ranks for a query nobody wins.
Common mistakes
- A hashtag block instead of sentences. Instagram caps hashtags at five, and a tag isn't a sentence Google can quote.
- Putting the keyword only in the audio or the on-screen text. Google has no proven access to either. It has to be in the caption.
- Hashtags in the first comment. Instagram's own guidance is that keywords and hashtags belong in the caption to be searchable.
- A professional's content on a personal account. Not indexed. Switch to Business or Creator and check the search-engine toggle.
Frequently asked questions
Do Instagram captions help SEO?
Yes. Since July 10, 2025, Google indexes captions, alt text and Reels from public Instagram professional accounts. The caption is the main text Google reads, so a caption that states the question and the answer in plain words can rank for it.
Do post descriptions affect reach or virality?
No. Reach is decided by how viewers respond to the video itself. Instagram has said hashtags are a search and categorization signal rather than a reach lever, and the same is true of the rest of the caption.
How many hashtags should I use on Instagram in 2026?
Up to five. Instagram capped hashtags at five per post and Reel in December 2025 and says fewer, more targeted hashtags perform better than many generic ones.
Does Google index TikTok and LinkedIn posts?
Yes. Public TikTok pages and public LinkedIn posts have been crawlable for years. Google reads the caption or post text, the hashtags and the creator name, not the spoken audio.
Can AI write my social media post descriptions?
Yes. A prompt file fed the video transcript or the post text can produce a search-ready description in one pass. You still check it against what the video actually says before posting.