While the internet is full of interesting and handy information, most of the websites on it aren't necessarily what you should use as source material for a research assignment. Some problems with using websites found by searching Google include:
(These go for Wikipedia too)
Here is an example of a basic search about the Great Depression. According to the search, there should be 208 million websites related to the topic...right? Not exactly. About 99.9999% of those 208 million websites will be of little use. Most websites will be unusable because of the problems listed above, or because they don't actually contain information about the search topic.
For example, the first three results include a public school district, the History Channel's website, and Wikipedia; none of which are considered scholarly enough for research material (but they are ok for general information purposes).