3. From The Forums: A post on Reddit showed a graphic that displayed Bitcoin Hashrates hitting all-time highs. @Stepjenvsawyer posted, "Why? What does this mean? What does it signify?" I'm glad he asked that because he got a slew of great answers.
@GeneralJenkins responded, " A network's hashrate is the most important data point in blockchain tech. Essentially, the hashrate describes how much computing power is being thrown at the network, by users all across the world.
If you want to attack bitcoin blockchain you need to have a higher hashrate than the rest of the network (51% Attack). This becomes more difficult the more hashrate the rest of the network has. So more hashrate ideally means the network is safer. Smaller coins often have a low hashrate and therefore are more likely to be attacked."
@Suninabox added on by saying," Only if the attack is an entirely new player with no relation to any existing miners trying to single-handedly produce 51% of the hashrate. For an attack like, the Chinese state seizing every miner in China, or several large mining pools forming a cartel, or the manufacturer of most of the hardware backdooring that hardware, overall hash rate is irrelevant, and distribution of hash rate is only mildly relevant.
If the overall hash rate increases, but it's concentrated in fewer miners then that means fewer points of failure which makes it weaker to lots of attacks."