The online presence of organizations is long gone from being just a web page. Social media have enabled easy and inexpensive interaction between millions of individuals and communities. This has not gone unnoticed by cultural heritage institutes. The question is what all these social media activities bring. Even if an institute knows what it tries to achieve online, the metrics often consist of confusing accumulation of statistics, across several systems and reveal little about online user behaviour, engagement and satisfaction. In the research project Museum Compass a prototype of a social media monitor is developed, which will contain data of current and historic online activities on Facebook, Twitter, YouTube, Foursquare and Flickr of all registered Dutch museums. The first version of this monitor has been developed, and we believe that this is a good moment to discuss – mostly in a practical sense – our general approach and preliminary results.