In one sense the Internet is no different from other information sources. Some information is free, some has to be paid for.
Some information is of high quality and highly relevant to the research problem in hand.
Some information is of low quality, is irrelevant and may even be described as junk. One popular misconception about the Internet is that it is a source of free information about everything. Much of the information on the Internet which is of value for academic research has to be paid for, and often it is far from cheap. The library pays for some of this information and makes it available from the databases page. Always remember that there is a lot of information which isn't available on the Internet at all.