To find things on the Internet, most people just use Google. However, most of the pages that Google finds are not scholarly. You can use these non-scholarly sources as stepping stones, to get ideas or to get a broad overview of a topic, but you generally shouldn't cite non-scholarly sources.
A good example is Wikipedia. Wikipedia is not a scholarly source. It doesn't provide any original information; instead, it collects and reproduces information from other sources (which are listed in the footnotes of its articles). It's okay to use Wikipedia as a stepping stone to other sources, but don't cite Wikipedia itself.
If you're looking for scholarly sources on the Internet, try these sites:
Here are a few quality websites recommended by UMW librarians. These websites are useful for a broad variety of subjects. You may also want to view the UMW Libraries subject guides, where you'll find lists of websites for particular subjects (such as biology or history or political science).