Social media platforms like Facebook and Twitter form an increasingly important part of our overall media ecologies. Though sometimes criticised as merely ephemeral spaces for incessant chatter, they come to the fore especially at times of crisis: tracking unfolding acute events from natural disasters to political crises in a more complex and comprehensive way than almost any other medium is capable of. They provide real-time indications of contemporary popular interests, as well as constituting a rich historical record of how major events unfolded and were received by their publics – and for both these reasons, they are well worth archiving. How national and global audiences responded to events like the Japanese tsunami or the death of Osama bin Laden will be of significant interest to future researchers, for example. Additionally, in many cases, simply capturing social media content at large scale is relatively easy; processing and evaluating it is considerably more difficult, however. This paper will outline what's possible – and necessary – in this context.