Why HTML is not good at representing Information on the Internet？

I try to use the following contents to explain why HTML is not good at representing the Information on the Internet. On the other hand, I want to show you why we replace HTML with XML.

HTML is good at showing the layout of the Web Page. For example, we can use the , tags to represent the table form on the Internet. In other words, HTML is suitable to show the docuements to users. But, if we want to use HTML to exchange informations, it will be very difficult.

See the following HTML :

<tr>

<td> aaa </td>
<td> bbb </td>

</tr>

It will show a table on the web page when we use and tags.

Now, we will use a crawlers to grab some informations from many web pages and show the information to our customers, it will be very very difficult to write the program. Because different web pages will use different HTML tags to represent data. The page A use <td> and page B use < ul>. Our program have to deal with different situations...damn it！

If we can use some meaningful tags such as tag to represent the price and tag to represnt the name, it will be great！

XML can make the world better.