Why do you say “user agent” everywhere, instead of “browser”?
Although browsers are indeed important users of HTML and XHTML, there are other programs and systems that read those documents. Search engines for instance read documents, but are not browsers. By using the term “user agent” we are trying to remind people of the difference. For example, when you do a Google search often you will see under some of the search results something like “This web page uses frames, but your browser doesn’t support them.” therefore surely frightening off some people from clicking on that link. The author of the website in question hasn’t realised that there are more than just browsers, and that they ought to include better text in their