If you're looking for more up-to-date information about Titan's capabilities then check out these posts.

Titan underwent major changes to optimize in-memory operations. Here is some up-to-date info on that: http://thinkaurelius.com/2013/11/24/boutique-graph-data-with...

IIRC, the euranova benchmark doesn't discuss scalability. This post does: http://thinkaurelius.com/2013/05/13/educating-the-planet-wit...