Looking at https://holochain.org/ , most of my scam senses are not going off tooo much. Its got some weird testimonials and then a white paper! So far so good.
Ok, lets skip to the white paper. Now what I'm looking for here is mainly how do you verify computations are valid amidst BFT and sybil attacks.
So its got some stuff about how every message received can be verified by the receiver by using "validation rules". Okay... so we can use custom validation rules that each receiver can define and run themselves. Fine, one such rule could be Bitcoins proof of work.
So it can be as expensive as Bitcoin. Now of course there can be other rules that are less expensive of Bitcoin, but theres a big reason Bitcoin's PoW is so expensive... Its been battle tested and looked at by 1000s of people to verify that its correct and can resist just about anything up to a 51% bad node attack. Allowing any program to define its own set of validation rules in the hopes that they will be faster doesn't make things safer. It just makes it more likely for fails. This looks like the major contribution that Holochain is trying to make. Let everyone write their own proof of work functions that suits their needs and mess it up. The number of ethereum dapps that failed to write safe contract is proof enough that this will happen in an identical fashion.
Did I miss something? Maybe there really is something here thats new, but I'm not seeing it at first glance. Its doesn't look a scam though so its got that going for it