Ethereum, the second biggest cryptocurrency as far as capitalization is concerned, is often called Bitcoin 2.0.
It cannot be exactly considered a new and better Bitcoin, mainly because it is differently oriented. While Bitcoin uses peer-to-peer electronic monetary system, Ethereum aims for creating a platform for decentralized digital assets. Another difference is, that there is a limited number of mineable units of Bitcoin and no new units cannot be created. Ethereum is not the same.
As has already happened in past, new units can be created. But it is also set up in the algorithm, that with every increase of the number of units, the mining algorithm increases in difficulty. They are similar also because of their algorithms. Ethereum uses KECCAK (or SHA-3) algorithm, which is quite similar to Bitcoin’s SHA-256 algorithm.
One interesting event concerning Ethereum was a split of the site. Some users disagreed with the split and therefore cryptocurrency Ethereum Classic originated. However, most of the community and developers agreed supported the split.