It's back online: https://steemchart.net
The site was down for some time, because I was having problems fetching the data. Turns out they fixed the API, so I spent a few days to again fetch the entire history and here we go.
Fetching trades live is easy, but getting the entire history since 2016 takes a long time, because you can only get 100 trades per http call. I'm thinking about releasing the source code but currently it's not in one single piece.
I'm using this python library to interact with Steem: http://steem.readthedocs.io/en/latest/