On Facebook and Google Plus you can see the original post, who posted it, when and all of the comments that follow. How do they save the posts, then load that data with php? XML Files?
closed as not a real question by DisgruntledGoat, Su', John Conde♦ Aug 13 '12 at 10:57
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Google is most likely saving data into Big Table.
Facebook probably a similar nosql database, they load with AJAX