first of all let me thank you for this great and phantastic working plugin! Very good work, it's exactly what i was looking for! :-)
There is one thing i've noticed: It seems sometimes to slow down the loading of my website in a quite remarkeable way. I assume that this may happen when the plugin checks the fanpage for new comments, the reaction times of the facebook servers are quite not the best ;-)
I have one suggestion for this:
Is it possible to supply a php file which can be called by a cron job on the server? This would get the load away from the apache process right at this time where a user triggers the fetching by calling the site. The site would remain as fast as before.
The "old" method could be left as an option for those guys who are on a shared hosting without the capabilities of creating a cronjob.
It's just a theory that it works like i think about, and this causes the delay ... but if, i think the above solution would solve this.