Not really bud, I know the exploit. It bypassed their countermeasure for direct linking to/execution of JavaScript code. Within a personal site it's not uncommon for a developer to use [a href="javascript:alert('test');"] ... but it is uncommon for someone to link to such a code snippet on FB. Why EVERY URL submitted to their network wasn't (or isn't) sanitized is beyond me. This method simply avoided the need for the user to copy & paste the code; hence it's high success rate and insane level of virality. But the script itself did no cross-site-scripting. You may be considering the action of getting around FB's countermeasure as XSS, but if anything, at best it's considered an exploit, at worst a bug or overlooked/unpatched issue within their news feed.
XSS is highly advanced shit and requires more than just running basic AJAX. For example, some rely on buffer overflow exploits within the operating system to execute their scripts. Fundamentally it requires breaking the limitations of the scripting language development platform (JS/VBS/etc), browser safety, and OS safety, which is why almost all XSS exploits arrive via 0day groups and the like. To put it simply: true XSS can't be patched by FB tweaking their shitty site, it's addressed by OS & browser patches.