Have you ever posted a comment to Facebook only to notice later that it included grammatical or spelling errors or another, more embarrassing gaffe? Facebook feels your pain, and will now allow you to edit the comments you make on the social network. "This is particularly useful if you've made a typo within your comment but already received some likes," a Facebook spokeswoman said in a comment. "Now you won't have to delete the comment entirely, just edit it." So, if...