In a post from almost five years ago, Rand Fishkin segments search queries into four buckets to uncover potential searcher intent: navigational, informational, commercial investigation, transactional. While this post is a fossil in the internet marketing world, the approach and information is still valid.

As Fishkin explains, we as search engine users showcase our intentions through the words we choose to query.

Our semantics show what we want, and to some extent, what we expect. He goes into some detail about how he categorizes these four segments:

• Navigational search is when a searcher is looking for a pre-determined destination. Think of the people, most likely your parents, who still type a domain name into the search box.
• Informational search probably covers the largest bucket of keywords, and is generally representative of users looking for a quick answer. These are people looking for a phone number, directions, or even a piece of recent news, such as a sports score or headline.
• Commercial Investigation is, as Fishkin notes, "straddling the line between research and commercial intent." These are queries where the searcher is looking to gain information to help them inform a buying decision, even if they do not convert; this is the gathering of information that has the potential to later lead to a sale.
• Transactional is the obvious one: these are queries where the searcher is looking to make a purchase, find a place to make a purchase, or complete a task. These can range from queries looking to make a purchase online, to looking up the address of a store, to signing up for a service.

To take this one step further, Fishkin assesses the potential value of each intent segment, exploring the average opportunity value of each type in relation to conversions, with navigational being the lowest and transactional being the highest.