The Steem blockchain (short Steem) or the Hive blockchain (short Hive) is first of all a platform for blogs on which everyone who is registered there with an account can publish own contributions and comment such posts. Blockchain only means that all contributions and transactions are stored in a chain of individual blocks and that this chain cannot be manipulated afterwards. Should this be attempted on one of the computers who manage the blocks of the blockchain, all other computers involved would recognize and prohibit this action.
To be able to pay for the deployment of the computers that manage the blocks and build the blockchain, there is a native currency on the blockchain. Just as bitcoin is at home on the bitcoin blockchain, it is the coin STEEM on the Steem blockchain or the coin HIVE on the Hive blockchain.
Like on twitter e.g. it is also a concern for the users of this blockchains to reach many followers. Anyone can give posts and comments of other users a like - called upvote. The special thing is that such an upvote has a monetary value, which is calculated in the native currency of the blockchain.
Steem-Engine, a side blockchain of the Steem blockchain, and Hive-Engine, a side blockchain of the Hive blockchain, allow you to create your own coins and trade on the exchange of the same name. Here you can buy and sell various coins against STEEM or HIVE. The coins on Steem-Engine or Hive-Engine are e.g. like the many coins on Ethereum (another well-known blockchain). To be active on Steem-Engine or Hive-Engine you need to transfer STEEM or HIVE from your Steem or Hive account.
Current information is always published on the Steem blockchain and on the Hive blockchain!
To go directly to CO2Fund's blog usually you can add /@co2fund to the web portal's URL, e.g.