what is this Bitcoin BU every one is excited about?
It's a currently consensus compatible fork of core that give the user the choice to set their own limits. Miners can choose how big their blocks are, and nodes can chose how much traffic they spent and what maximum blocks they accept. So under some conditions BU will change consensur critical rule of core and start a hard fork.
If a miners releases a block with 1.1 MB and your node just accepts blocks untill 1 MB, your node keeps both chains untill the chain with the bigger block reaches some user-configurable depth. Then your node assumes that this chain is correct and jumps to it.
Fans of BU claim that it would lead to an emerging consensus about the blocksize and that with BU the market decides the blocksize, not any kind of politbureu-developers (not matter if core or gavin or mike or jeff).
Critics of BU say it can't work cause of game theory and some attack scenarios. Also some say it would weaken the confirmation consensus if nodes are capable of keeping two chains separate for some blocks.
The developer behind BU is theZerg, who refuses to post on bitcointalk cause he and his mates have been banned cause they discussed forking bitcoin. Another one behind BU is Peter_R, who has recently banned and unbanned from reddit and character assasinated by the usual suspectives. He recenly said - what I think is very interesting - that BU is the only client that can deal with forks and if we expect a scenario with chaotic hardforks, BU can help to deal with it.
theZerg said to me his orginal idea is to take as much as possible out of the consensus to make Bitcoin more flexible and to create an open environment for open development. This could help to develop bitcoin without hard- or softforks and envision a scenario where a very few consensus critical things, like the 21M limit, will never be changed while everything else is on a continuous vote.
There is a thread on bitcointalk in which Adam Backs wantet to review BU. In the end some posts have been deleted by commentators and even Adam Back confirmed that bitcointalk is not a neutral place to disuss things. After talking wih Lauda and after my personal experiences I don't share this. But I'd think there are indicators that Adam Back didn't want to review BU independently, but made his judgement bevore the discussion even startet (on reddit he said a few minutes after his initial post on bitcointalk that BU was already broken, without proofing his claim).
The thread is quiet interesting and, if you ignore the usual small block militia (that insults, prejuduices and dumbly repeats problems answered pages bevore) you have an interesting read
https://bitcointalksearch.org/topic/bitcoin-unlimited-seeks-review-1312371edit: an example for small block militias reading competence is hdbuck right here
bitcoin unlimited, as in unlimited blocksize..
He was told so often that BU is NOT about an unlimited blocksize. It's about user's voice. With BU you, as a node, can even vote for smaller blocks, and when things come as they come and 1 MB blocks are too much for miners and nodes, they would be cut to say 0.8 with BU. As you wish small blocks and high fees, BU would give you the option to express this by setting the blocklimit. If miners think the same blocks will ever kept small.
But to be honest, the economic theory behind BU is that there already is a fee market whose mechanics are the orphans. There is a paper from Peter_R about it. It says a fee market doesn't need no blocklimit. But I think he didn't took the relay network into perspective, so this fee market currently doesn't exist, but maybe will exist with bigger blocks.
