Programmers tire of repeatedly solving the same problem, and XML has helped to avoid this.
XML is a means of making data more accessible to applications. You might well ask, "Surely database do this already", but sometimes you do not want or need the overhead of a database and a simple text file will suffice.
In fact that is just what XML is, a text file. As such it is about as portable as information can be. However an XML file is rigorously structured, and this has a number of advantages.
The rigorous structure facilitates the interpretation of this text file, and its conversion to other formats
An example might help clarify the use of xml
<customer><name>Bob</name><age>45</age></customer>
This simple, and incomplete extract of an XML file tells us a number of things. The file stores information about a customer called bob who is 45 years old.
It is easy to look at this file and deduce its meaning. XML is almost self documenting.
At Meadowlark we use XML in our Flash ActionScript applications