Bitcoin Forum

I've heard of other cryptos such as Litecoin. I was wondering how are they similar/different to BTC? and if their are any other cryptos that are worth looking into?

I also know Namecoins (NMC), but also dont know the exact idea behind it

Good summary here: https://bitcointalk.org/index.php?topic=134179.0 (https://bitcointalk.org/index.php?topic=134179.0)

nearly each one has a different approach.

namecoin is a merged mining cryptocoin.  thus its protection from a 51% attack comes (mostly) from bitcoin miners who mine namecoin with no additional work performed.

ppcoin has a proof of stake.  this is a different type of protection from a 51% attack where those who already have coins have a say what a block includes, and not just the miners.

litecoin is a proof of work cryptcoin, but it uses a different algorithm for the mining work.  it uses scrypt instead of sha256 and since scrypt uses a lot of memory, there are no fpga devices for it (yet, maybe?) and definitely no asics for it.

consider all the worry about a "lot of computers" hurting bitcoin, and litecoin has just like 2% of the amount of mining (protection) that bitcoin does, and even fewer nodes.  there are a lot of unused gpus around now that could be used against litecoin and exceed that 51% threshold.  there isn't much of an economic reason to do so.  if you were to sell litecoins at the exchanges like btc-e, vircurex and others for some bitcoins, this 51% could then double spend those ltc deposits to the exchanges, but what could you buy using those litecoins after?

if litecoin were to be 51% attacked, there's nobody that would take those litecoins after the attack.  so litecoin is pretty vulnerable to a 51% attack (relative to bitcoin) yet but it hasn't had that happen yet and who knows if anyone ever will.