Originally Posted by rowan

Many of them have no real value apart from making money with speculation or hype... including pre- or "almost" pre- mines by the developers and their buddies. There's even software that mines the most profitable coin at the time, then optionally auto-sells (dumps) it.

Litecoin is really the only coin that tried to do something different (using scrypt), the rest are mostly just some simple tweaks to the block target and difficulty. Any idiot who knows how to modify some values and compile from source can do it.