Grabbing data from another web page can either be illegal or a last ditch effort to overcome a data issue. The industry pet name for grabbing another web page and parsing out the needed data is called "Screen Scraping".
Note
Remember, screen scraping a website that we do not have permission to use the data from is illegal and can land us and our firm in a lot of unnecessary hot water!
All the legal mumbo-jumbo aside, screen scraping has many legal, and purposeful uses. To implement this recipe, imagine a scenario whereby the menu of one internal, company-owned website needs to be displayed within an area of another, separately maintained, company-owned website. Using a web service or other XML feed is one way to handle that; but experienced programmers know, we can typically scrape that data and redisplay it before the initial XML specifications can even be documented.
Screen Scraping 101
Scrape only pages that we are licensed to scrape...