So I recently found out the hard way that Facebook likes to cache sharing meta information for pages which have been shared on there.
I was working on a site where I was testing some social media sharing functionality for some video pages I was putting together, and I accidentally included the wrong thumbnail image in the meta data on one of the pages. I shared the page privately via Facebook to test it and Facebook cached the meta data I’d used. Even after I changed the image to the correct one it was still showing the old cached one. As it’s not cached by your browser you can’t just clear your cache, it’s actually cached on Facebook’s servers and will be viewed in it’s cached state by anyone who shares that page on Facebook (I had someone else try sharing the page via their Facebook account and the old image still showed up). I tried deleting the page on the web server and reuploading a fresh version – still didn’t work. I’m sure that Facebook recrawls the pages at set intervals, but in the 24 hours period I was working on this it wasn’t recrawled and I didn’t have time to wait.
Simple. Go to http://developers.facebook.com/tools/debug and enter your page URL. Facebook then recrawls the page and shows you the meta data that it sees and will use.
You learn something new everyday…