Edit: actually it does appear a goal is to share computing power though I know less about those details compared to the data distribution. Ref: https://forum.safenetwork.io/t/homomorphic-encryption-by-mit...
Citation needed, the only thing I've seen maidsafe do is take peoples' money
1 - https://forum.safenetwork.io/ 2 - https://maidsafe.atlassian.net/ 3 - https://github.com/maidsafe/
I have been watching http://www.zennet.sc/ which is the closest I have found but maidsafe seems pretty interesting as well.
You are correct about using stored work to pay for other compute being interesting. I believe this is actually the nature of reality, not just some new fangled thing we're getting around to 'inventing'. I will note this is an opinion of a futurist, so it is what it is.
At the least, compute federation is enabled with cryptocurrencies. They give you a way to pay for use (payments), identify with them (identity managment) and a way to standardize the use of the compute (immutable data structures).
One of my friends informed me that the idea of currencies backed by computing power has existed for a long time in science fiction so perhaps we'll see these specific kinds of systems soon.
The most important idea imo is that companies can never claim ownership of personal data because they never have access to it. Another cool idea is that if you have a currency that can be cashed in for fractional computing power on the network you could pay tech companies in computing power, either providing it from a device you own or paying for it with the currency.
I look forward to the papers/code that they release.
Edit: I'm not really clear on this, is there any currency component to Enigma? I was thinking there could be a currency that's a transferrable debt of fractional computing power of the network.
Edit 2: Apparently it isn't a currency and uses bitcoin for fees...