Slate developed a computer program to find as many comments deleted from Sarah Palin's Facebook page as possible without bombarding Facebook's servers. Every three minutes during the first 24 hours after Palin posted a note, we would check all the comments on that note. If a comment appeared during one check-in but later disappeared, we considered that comment deleted.
For tech enthusiasts only, a more thorough description follows.
• Checked Palin's Facebook fan page for any new notes. (All Facebook data came from the site's Graph API.)
• Found all available comments on notes published within the past 24 hours, and compared these comments against an SQLite database of previous comments.
• Added new comments—those that appeared in the latest list of comments but not the database—to the database.
• Marked comments as deleted if they appeared in the database but not on the latest list.
Caveat: The program would have missed comments that were posted and summarily deleted within any of its three-minute windows. Many of these deletions might have been from users who erased impulsively posted comments themselves, though it's impossible to know for sure.