You can store plenty on the Datacoin blockchain if you mine for a few days.
It has a 128KiB transaction field for arbitrary data storage.
Interesting, I looked into it. It seems as though it's like an ASIC proof bitcoin with support for a larger "OP_RETURN".
I personally don't like the idea of storing data specifically on the blockchain since it stays there forever and storage prices will increase exponentially with demand.
However, according to the FAQ,
http://datacoin.info/faq/, it seems as though they will have a personal chain thing for specific services.
It seems more interesting and scalable.
Personal chains will start from the root Datacoin blockchain and will be replicated to nodes by subscription (nodes can choose chains they subscribe to). The Datacoin blockchain will handle only identification and some metadata for all personal chains.