I THOUGHT DTC was basically a utility token feature of Steem. I'm guessing it's tied to Steem's distributed infrastructure somehow?

Actually no it isn't. The best way to think of the relationship of DTC & STEEM is like a kickstarter program ... we started on STEEM to make use of the economy to build a project like many of the various dApps but unlike anything still working directly on STEEM Blockchain we built our own completely separate. Avalon distributes the DTUBE Coin(DTC) and the only relationship left between the chains is that the DTube front end allows cross posting and displays information from those posts while DTube has curation accounts for voting good content on all 3 chain posting options.

Feel free to use anything by OneLoveDTube and yours truly @d00k13