Real-World XML
Monday, December 15, 1997 by Dave Winer.
Everyone talks in hushed tones about XML. Shhh. It's exciting! But what does it do?
I can't get involved with something without immediately trying to ground it with an application. How else could I know if it's worth exploring?
Luckily, I had an application waiting for XML.
siteChanges.xml 
Jump to this page, and if necessary, view source to see a real application of XML.
http://www.scripting.com/siteChanges.xml
A scheduled script produces that file, running every night at 12 midnight Pacific. It scans our server for new pages, or pages that were modified in the last 24 hours.
A search engine like Alta Vista, InfoSeek, Newsbot or Excite could read this page every night at 9AM GMT. They wouldn't have to crawl the whole site to find the pages that changed, as they do now, they could just load the pages that have changed since the last time they visited.
How was the file generated?
It doesn't matter!
One bit of software can talk to another, and all they need to agree about is the format of the data they want to exchange. There's nothing interesting about how the information is generated (mod dates are a common feature of all current operating systems). What matters is that there's a format that can be understood on all operating systems.
So even if we use PERL running on Solaris to create the XML-based info, you can read it on Windows 95 running Microsoft Access, or on an IBM mainframe running Oracle, or Rhapsody running Sybase, or an ancient CP/M box running dBASE II.
It doesn't matter. That's the magic of XML.
It's about relationships
XML allows sites to easily establish an ongoing relationship with search engines. Each machine does what it's good at doing. Network traffic is minimized. The best picture of our site assembles itself on the search engine server.
On our LAN it's easy and fast to find all the pages that changed. Why should a search engine struggle to find this information when we can easily generate it? There's no need.
We've been waiting for an agreed-to format for this functionality. I think every webmaster will recognize the value of maintaining this information. We need agreement with the search engine companies. If you represent such a company, please send me email so you can be included in the discussion.
I think we need a practical example of real-world XML.
This may be the first one?
Is XML just hype?
No, it's not. Unlike some other industry initiatives, there are applications waiting for XML. I wouldn't be involved if that weren't true.
XML can go somewhere. First search engines, then caches running on your LAN, then sandboxes running on each machine.
http://www.scripting.com/davenet/97/04/Sandboxes.html
We're going somewhere...
Let's have fun!
Dave Winer