You continue to produce a great plugin here. Considering how complex this thing is, I'm amazed you have it all working smoothly.
I have one issue and one request. First the issue.
Any comment posted at Facebook that's mirrored back to the post at the website has a timestamp that's an hour ahead of its actual post time. Normally it wouldn't matter, but if a lot of people are commenting on something, all the Facebook comments are pushed to the bottom of the list in WordPress because they always have a timestamp farther in the future :-/
Do you know why this happens or why the comments coming from Facebook get the wrong time? Is that a setting at Facebook on the page admin's account or something?
Second, one request. I'm happy to see you have a better solution for the $message situation. The fact you have to do that to keep Facebook from grouping links is a bummer. I'd like to request that you give the user an option to specify the text. You're pulling the site title, but I'd rather it say something like "Just posted at my site.com". I actually went into the init.php file and hard-coded that, but it would be great to just have it as an option in settings.
Let me know if you know what the deal is with the timestamp. Thanks!