I've actually seen crossposting happen from DW to Tumblr, in the sense that you post on DW, and then there's a crosspost to Tumblr with an automatic "read more" that takes you to DW for further reading/commenting. I'm gonna look into that further to find out how that works, and see if it's something I want to bother with. I might not, because it could mess with privacy settings and such, but yeah. Definitely gonna look into it.