The long tail is the mass of queries with low individual search volume at the long end of the distribution curve. They're often specific, but the length of the phrase isn't what defines them.
What is the long tail?
A handful of generic queries usually have high search volume. Next to them sits a large number of less frequent phrasings that can describe an exact situation, product or question.
For example, "running shoes" is a generic query. "Waterproof shoes for winter trail running" is a narrower need, but you still have to check its competition and commercial value.
Why the long tail is worth your time
A more specific query can reveal the intent better and allow a more precise answer. For a new site, it can also open topics the big competitors don't cover well enough.
Not every long-tail query has lower competition or higher conversion, though. Some narrow B2B and finance queries are very valuable and very competitive.
How it connects to AI search
Conversational interfaces encourage longer and more complex questions. Query fan-out can then split them into several related searches.
So build content around the need and its context. The exact phrase length matters far less. One good page can cover several head and long-tail queries with the same intent.