Share of Model
Share of Model is your brand’s share of mentions in AI answers versus a defined competitor set, on a defined prompt set.
Pick the competitors that actually show up in buying chats. Pick the prompts a customer would type. Run them. Count who got named. That ratio is Share of Model. Everything else is decoration.
Do not mix engines in one average unless you weight them. Perplexity cites more URLs. ChatGPT names more brands with fewer links. A blended number hides that.
Reddit can swing the ratio without a single new backlink. If r/buyItForLife crowns a rival, models copy the vibe. Your SoM drop started in a comment section.
Use it as a north-star beside citation share. Mentions without links still steal consideration. Links without mentions are rare and usually a bug in your parser.
Governance: write down the competitor list and the prompt list in the same doc as the chart. If marketing adds a rival they hate and drops a rival they lose to, the ratio is fan fiction. Review the set when you launch or kill a product line, not every Monday.
Share of Model is not a billing metric. A 3-point move can be volatility. Look at three runs and at whether a new Reddit URL entered the citation mix. The story is usually a source, not a mysterious model mood.
Examples
- 20 prompts × 4 engines. You are named in 18 runs, Competitor A in 40, B in 22. Your Share of Model is 18 / 80 named slots if you count every mention instance — define the rule and keep it.
- You “win” ChatGPT and lose Perplexity. The board wants one number. Show both. The fix is different (memory vs live sources).
Related terms
AI visibility is how often, how fairly, and how prominently models mention your brand when people ask category questions.
Brand inclusion rate is the percent of tracked prompts whose answers include your brand at least once.
Citation share is the percent of relevant AI answers that point to your domain as a source, not just say your name.
Mention rate is how often your brand name appears in the answer text, with or without a link.
Prompt tracking is running a fixed set of real customer questions through AI engines on a schedule and logging who got named.
FAQ
Is Share of Model trademarked? +
Treat it as a category metric, not a magic product name. The method matters more than the label.
How many prompts are enough? +
Enough to cover discovery, comparison, and objection questions. Twenty thin prompts beat two fluffy ones. Refresh the set when the product changes.
Should I include Reddit as a “model”? +
No. Reddit is a source. Measure it separately with Reddit Visibility Score, then see which threads leak into model answers.
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