 Usability can vary widely between selection-based search systems based on a large number of variables.Even the most basic selection-based search systems will allow more of the web to be searched by the user in the context of their work than any one stand-alone search engine.On the other hand, the process is sometimes said to be redundant if the system applies no intelligence to categorizing the selected text and matching it to an online service, and simply provides a link for the user to their preferred search engine(s).