I have been working on my side project to watch the status of open data portals. Unlike the dataportals.org, this project aims at presenting more insights into each listed data portal, including its dataset count, tags, categories, and publishers. This information is collected every week for all supported data portals so that I can maintain the history of how the data opening was being improved.
Now more than 100 CKAN-based data portals have been covered and I am working on the support for Socrata-based portals (200+).
You can take a look at the result at OpenDataDiscovery.org.
This project is open-sourced at GitHub. If you are interested in the status at historic moments, the historical data is also downloadable at the project website.
Please let me know how do you think about it