Google Trends
Google Trends shows how search interest for a term changes over time, relative to its own peak - indexed to 100 rather than raw volume. You can compare terms, slice by geography, time period and category, and see seasonality. For SEO it's the sanity check on keyword research: it tells you whether a market is growing, seasonal, or past its peak, and which way interest is actually moving.
Why It Matters
Trends answers the question volume data can't: is this market growing or shrinking? A keyword with big volume that's declining year over year is a trap; one that's climbing is an opportunity. Trends also reveals seasonality - the businesses that build content ahead of the seasonal spike beat the ones that publish during it.
It's also the honest tool for choosing between bets. 'Is anyone searching for this?' is a question tools answer with estimates; Trends answers it with direction and comparison. For content strategy, knowing which of two topics has real, growing demand is worth more than any volume estimate.
In Practice
Compare your target terms over the last five years, not twelve months - the trend is the signal, not the season. Check the geographic breakdown: a national term that's flat can hide strong regional demand. Use the related-queries feature to discover adjacent topics you're not targeting.
Use Trends before you commit content budget. A topic on the upswing with rising related queries is where you build authority; a flat or declining one gets the maintenance treatment, not the investment.
Common Mistakes
Reading a Trends spike as a durable trend when it's a news blip, or comparing terms with wildly different absolute volumes as if the index makes them directly comparable. The 100 is a relative score - use it for direction, not magnitude.
Sources & Further Reading
Where to verify this yourself - Google's own documentation, industry reporting, and how we apply it at Underdog. Don't take our word for it; check the source.
Related Terms
Glossary
Keyword Research
Finding what your audience searches for - the foundation of every SEO strategy.
Glossary
Search Intent
The reason behind a search query - matching it is more important than matching keywords.
Glossary
Long-Tail Keyword
Longer, more specific search queries - lower volume but higher intent and easier to rank for.
Glossary
Topical Authority
How comprehensively your site covers a subject - depth beats breadth for rankings.
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