It does put them in your "blog", @biasnarrative. Just like it does with dTube, dMania, dSound posts. Check my previous post. ;)

Currently that is because there is no flag like do_not_not_show_on_steemit available to developers and Steemit acts as the everything bucket.

If I understand it correctly SMTs will solve that and platforms operating their own SMT will not be shown on Steemit/other platforms. Maybe there will be a flag do_show_on available but I haven’t found that info in the SMT paper.

Hopefully the block chain will soon be updated with such an option because otherwise things may become annoying. Witnesses may want to bring that up and speed up the development of that but then again for many it would mean less exposure for their new projects.