Toolbar: A search toolbar generally plugs into a browser and becomes an internet user's primary method of internet searching. Toolbars feature convenient placement and quick access, since users can click into them without leaving their current page. Users don't even have to go to another website to do a quick search.
Many major search engine providers distribute search toolbars to gain marketshare. Some of these toolbars simply search the web. Others may include extra features like pop-up blockers, safe search settings, spell checkers, and form autofill to promote user loyalty. They also help search engine track and compile usage data.
Many search engine toolbars look to enhance the query experience by offering a list of popular queries based on the first few characters typed by the searcher. They may also attempt to guess what the searcher is looking for by auto-completing a query.
Often, users aren't aware of how to change their search engine settings, so they may choose to go with the default toolbar even if it's not the engine they'd usually use. However, many users dislike unknown toolbars taking over their browsers as download add-ons or adware, and search results for "search engine toolbars" are filled with tutorials on how to remove unwanted search engines.