In the Ethereum Homestead docs there is a paragraph
But as bitcoin began attracting greater attention from developers and technologists, novel projects began to use the bitcoin network for purposes other than transfers of value tokens. Many of these took the form of “alt coins” - separate blockchains with cryptocurrencies of their own which improved on the original bitcoin protocol to add new features or capabilities.
1. What are the best examples of such 'other purposes' and projects, especially the ones that are not altcoins?
2. What are the most prominent altcoins that haven't lost their significance?