Journals and magazines are generally put into three categories: popular, professional and scholarly; and understanding how the information in them differs can be very helpful when determining their role in your research.
News and newspapers may often be written or presented with a bias - for example, selectively highlighting specific facts while downplaying others; or using specific terms that are inflammatory (i.e. the terms terrorists, revolutionary fighters, or freedom fighters may all refer to the same group across different sources. Being able to understand the bias found in news is vital in using it in your research.
If you are tracking a big story, it is also important to remember that news sites and newspapers, especially on websites, will rush to publish information based on what is known or suspected at the time; and the entire story might only be reflected days or weeks later as understandings change.
Web pages can be useful in research; but because of the nature of web publishing (cheap, accessible to everyone, and easy) there mix of information on the web range from useful to unverifiable to outright lunacy. When using anything found on the web, it is very important to evaluate it for quality, not only usefuless.