Answer:
According to facebook documentation if you use Facebook like button, then Facebook will scrape your page Facebook page every 24 hours to ensure the web page is current.
The page is also crawled when an admin for the Open Graph page clicks the Like button and when the URL is entered into the Facebook URL Linter.
The user agent of the scraper is: "facebookexternalhit/1.1 (+http://www.facebook.com/externalhit_uatext.php)"
According to facebook documentation if you use Facebook like button, then Facebook will scrape your page Facebook page every 24 hours to ensure the web page is current.
The page is also crawled when an admin for the Open Graph page clicks the Like button and when the URL is entered into the Facebook URL Linter.
The user agent of the scraper is: "facebookexternalhit/1.1 (+http://www.facebook.com/externalhit_uatext.php)"