How do rank checking programs work?

Anyone know how to programically determine ranking?

[Corey]

Is there any information out there on how to "programatically" determine your ranking on search engines? Several softwares do it, such as WebPosition Gold, Search Engine Commando, IBP from Axandra, or other web-based software.

What is the programming involved in doing this? Is it XML? And how difficult is it? Are there any resources out there that explain it?

By the way, if this is some sort of trade secret that should not be discussed, please feel free to let me know that as well. (Or email me)

Thanks!

[bakedjake]

Two ways to do it:

1. Screen scraping: Basically, you pull the page off of a standard HTML request, and pull out the data you need. With this method, you'll need to update your scraper algorithm whenever a SE changes their SERPS.

2. API call - Several search engines give you the ability to get SERPs through a standard, programatic process. If you'd like an example of this approach, which is the easiest, there is source code here on WebmasterWorld for interfacing with the Google API. Check out:

Command line Google Rank Checker [webmasterworld.com]
Visual Basic Google API Rank Checker Program [webmasterworld.com]