Hi,
"XML presents data in a meaningful way", This means , in HTML u have the tags from which u can find out much meaning in it.
Suppose u have three lines of address line in a paragraph tag. U cant differentiate which is city and which is pincode etc. But in XML , since u can define separate tag for pincode and city, it is meaningfull just by seeing the tag itself.
Hope this gives u an idea.
Arun
SCJP