@dm312, steemit.com is not a blockchain but a web application owned by Steemit Inc., it serves as a front-end to the blockchain, and there are other front-ends (i.e busy.org, esteem). Since the blockchain is currently "public domain" defacto (not regulated yet) virtually anybody able to build a front-end for the blockchain is free to profit from it in any way. This is similar to OpenSource, the source code is free, you can use it to profit the way you wish.
RE: Steemit Engineering Update: Continued Progress on RocksDB, Condenser Split and More