Scholar Metrics provide an easy way for authors to quickly gauge the visibility and influence of recent articles in scholarly publications.
Scholar Metrics include a large number of publications beyond those listed on the per-category and per-language pages.
This holds true to keep track of research productivity for scholars, specially because of increased competition.
Some of the work included in Google Scholar is not peer-reviewed and has been less rigorously scrutinised than the peer-reviewed sources included in Web of Science and Scopus.
While these items can all be useful, it is important to evaluate the sources for credibility.
Moreover, if you have any text selected on the page and then click the button it will display results from a search on those words when clicked.