I took the chance I was in Lisbon last November 14 to follow the events related to the European General Strike. I scrapped Facebook groups EuropeanStrike and 14n-Huelga and archived tweets with the hashtags #14n and #EuropeanStrike.
I thought this was an interesting opportunity to compare how protestors use the two social media platforms, and here's some interesting contrasts between Facebook and Twitter usage during this particular time of political unrest.
What follows is Twitter information stream #14n and Facebook information stream EuropeanStrike. I adjusted the timeline so both plots refer to the same time frame. It's clear that Twitter hashtag activity is far more intense than Facebook pages.
Twitter API provides information regarding the language Twitter users posted their messages. This is not a particularly reliable metric, but #EuropeanStrike shows a much higher-than-average number of languages.
Facebook Graph API does not provide as much information as Twitter API, but it does give you the exact number of "likes" and "comments" of any given post . The figures below show the diversity of Twitter languages and Facebook posts.
Twitter conversation has a lot more text than Facebook's. Twitter dataset is about 50 times larger than Facebook's, probably because Facebook users post and comment within their social network. The last two plots are word clouds from the datasets.