Question: What are user agents, and why are they important?
Answer: In the context of web servers, a user agent is any network host that connects to the server. Most frequently, it is used to refer to web browsers, but it can be other things as well. Anytime a search engine spider or other robot connects to your server, it leaves a user agent identity as well.
It is important to know about user agents because they can tell you a lot about your web site’s visitors and what types of computers they are using. Typical user agent data can include: browser brand and version, operating system brand and version, platform name, machine or processor type, and language. Some browsers allow users to specify what information to send or to send none at all.
Web server statistical software records user agent data and will display it for you in charts and graphs. You can determine how many of your users use a particular browser or operating system and make business decisions based on that data. You can also see how many of your hits and visitors are actually coming from non-human user agents. Overall, it is a very useful tool to have, and all website owners, big and small, should make use of it.