Tags can also contain attributes - additional information that is included as part of the tag itself, within the tag's angle brackets.
The following example shows an email message structure that uses attributes for the "to", "from", and "subject" fields:
<message to="you@yourAddress.com" from="me@myAddress.com" subject="XML Is Really Cool"> <text>How many ways is XML cool? Let me count the ways...</text> </message>
Since you could design a data structure like <message> equally well using either attributes or tags, it can take a considerable amount of thought to figure out which design is best for your purposes.