What stops me from doing this:

1. Control a large number of nodes.
2. On all except one, broadcast a chain that is always 1 block behind the main chain.
3. Suddenly from the last one release 4 blocks in quick succession. Now you win by 3 blocks (and don't trigger the 51% defense).

The solution to a 51% attack is never let one entity amass that amount.

There is none, high network hashrate would reduce the chances

This paragraph and the rest of white paper is full of nonsense unfortunately. First of all, not everyone who has 51%+ of network hash power is an attacker. One may mine blocks like anyone else and include other users' transactions in the blocks mined. On the other hand, one may mine empty blocks only and ignore other users' transactions completely, thus paralysing any coin movement on the network. It may be done with less than 51% of hash power to a lesser success though. Double spending is a different matter which involves two block chain forks with coins spent on one of them and unspent on the other which must become the primary chain eventually. Time warps are for difficulty manipulations at retargets. Finally, your defence concept is based on a false assumption of the attacker coming from a single IP or whatever you use for identification. There may be dozens if not hundreds of peers deployed worldwide for a distributed attack. There is no reliable decentralised solution currently to fight back 51% attacks of any kind.

Most of the above points are MOOT.
@ gmaxwell there is no CENTRAL checkpoint, all bans and checkpoints are done locally and in memory only
@ meta.p02 there are a few attacks that bypass this system, but this system was designed primarily to stop most attacks from being profitable.
@Hazard , Please don't talk about technical skill when you don't possess any.
@BitcoinEXpress Anyone with a significant amount of resources can break virtually anything that relies on p2p communication... this is meant to act as a stopgap measure, and as the number of nodes grow, so does the feasibility of this defense. Remember even when submitting with multiple nodes there will be a convergence point to a legitimate peer, and then that legitimate peer will be banned for transmitting too quickly, thereby segmenting the network for 4 hours but keeping many legitimate users safe.
@User705 Correct, it's possible to sloatboat your way around the system over time, but such an attack would be noticable and thus far easier to prepare for(on the dev side of things).
@ghostlander it's not based on the assumption of a single peer, remember that in p2p networks as the network grows larger there is always a convergence point, it will segment the network for 4 hours before allowing them to continue, the segmentation is limited by how many nodes the attacker controls and is a good defense for a large network.
@QuantPlus We don't post propaganda, perhaps you should look to one of the other altcoins? We've backed up every claim we've made to date.

Stop arguing over semantics, this was designed to stop some double spending attacks, basic difficulty attacks, and multipools(and it does that very well). When I say "virtual immunity" - I don't mean total immunity, I mean immunity from pretty much anyone out there who realizes that the cost of the attack would be greater than the gain.

The system is designed to cut off an affected portion of the network in the event of a multi-pronged attack, they will simply reconnect in 4 hours and continue on the main chain. This may make it unfeasible for something with < 100 nodes, but for bitcoin its perfectly usable.

The Goldcoin community is at least trying to do something for the crypto community to find somekind a solution to the 51% attacks. We have started something and from here on we build/improve it. To be honest I personally like all this critisme/advise, because it can all be used to improve this defense.

We excelled at spreading GLD.. so keep your delusions to yourself please, almost all of those coins were traded in the first week on cryptsy, https://www.cryptsy.com/markets/view/30 (view first week history).

Two, it is about liquidity as most people do not like holding 0.1 coins in their wallet, there is a psychological factor against dealing with decimals for people.

Akumaburn and AZIZ,

Why are you even bothering with this thread?

Did you ever notice how most of the old timers and serious developers do not have anything to do with him?

He is entertainment, plain and simple. He writes in a blog about developers he has never had any real conversation with and just assumes his observations are correct. He has a small band of newbies that cheer him on.

His 15 minutes will fade and another will take his place.

As the cypto community continues to grow, more like him will come on scene and he will be only a small voice among many others who proclaim to be "internet celebrities". The community will also grow in those that are of reasonable mind, and will work to make a difference and grow the community. Put your efforts into appealing to the later, and realize the former are nothing more then a daily chuckle.  

gmaxwell:

"It doesn't sound legitimate at all.
It sounds like the writing of someone...
Who doesn't even have a basic understanding of the problem space."

Heres a serious Dev pointing out...
The paper was a Promo Piece designed to give a false sense of security to GoldCoin owners...
And the last thing on earth we need is "help" from a bunch of Promoters.