Some people like to use frames on their sites.
Too many people complain of problems with frames than you can afford to ignore. So if you insist on using them, you'll need to create an alternative no-frames set of pages for these users. As If that wasn't enough reason, many search engine spiders also encounter difficulties with frames. This means you'll either have to spend additional time learning how to overcome these shortcomings or be doomed to low search rankings. In most of the situations in which you might feel you need to use frames you can usually use tables equally effectively.