When we think of a search engine like Google, we think of the main websearch function that you'd find on Google's main page. Google actually has a bunch of other search engines with more specialized functions. Those separate search engines are referred to as vertical search engines. Some examples from Google's past and present include:
- Google Maps
- Google Play
- Google Image Search
- Google Book Search
- Google Video
- Google Patent Search
- Google Catalogs
- Google Blog Search
- Google U.S. Government Search (Uncle Sam Search)
- Google Custom Search
- Google Scholar
- Google Product Search
- Google Trends
- Google Finance
- Google News
- Local Search
- Google Flights
- Recipe Search
These all are (or were) separate search engines that can be queried individually. Google has increasingly moved toward a universal search engine, but what that's really doing is what search engine wonks would call incorporating the verticals in the main results. Google uses what they know about common queries and semantics to figure out that when you type "red high heels" you might not be looking strictly for websites that mention high heels. You may want to see images of red high heels, you may have just heard something about a particular pair of shoes on the news, there may be a video that mentions them, or you may want to comparison shop.
The results will usually show a variety of suggestions and let you click on either a search result or enter a vertical search. You'll see links that say things like "More videos for red high heels," "Images for red high heel," "Shopping results for red high heels," or "News for red high heels." The position in your search results will depend on how probable Google thinks that's the type of result you want to see. In this particular query, news results came last. For some searches, you may also see a link to Google Maps.
Sometimes, rather than a link to take you to another search engine, you'll find options on the side to refine the search you're already making. Recipe searches often end up offering options on the left side of the window for calories or prep time.
Bing and Yahoo! have verticals as well. Most of the non-Google competition takes their queues from Google in this area, but over the years vertical searches have also developed completely on their own. Google Flight results come from a search engine Google acquired, but the search engine was originally developed to power comparison shopping engines like Orbitz and Travelocity. It still does, but the results are also incorporated into Google's universal search and can be queried from Google.
When Should You Use Vertical Search?
If you know what you want to find is an image, use Google Image Search from the start. Likewise with news, blogs, scholarly documents, or videos. Skip the middle man. If you can't remember where to find the specific search engine, you can actually just Google the name of the search engine to get there. You might think that it's just as easy to type in your original search query and click on the "Images for... " link, and often that's true. However, Google doesn't perfectly predict the type of search you need. Many times we enter search terms that are fairly generic, and there's no guarantee Google will figure it out.
Another thing to realize is when you've inadvertently strayed from the main search engine. You may have clicked on a vertical at some point in your search. That's usually not a problem if you've found what you're looking for, but sometimes that vertical ends up being the wrong path. If you're seeing a lot of results that don't make any sense, like only recipes or no results for something that should be easy to find, try going back to www.google.com and starting your search again.
If you're a business or blogger trying to get noticed, you might also be able to take advantage of vertical search. If you're lucky enough to place well in Google Image Search, for instance, you may find a lot of traffic from people who type in a generic result and end up realizing that they actually want an image. That's one reason many bloggers put images in every post. (It's not the only reason. Images are also eye catching in social media re-posts.)
Sometimes a search will reveal a vertical you didn't even realize existed. Try clicking on it to see what you can find.