subreddit outreach is a tricky business.
many communities will likely see this tactic as an attack on their community.
we have had threads in /r/cryptocurrency and /r/bitcoin deleted in the past.
there is a major project underway with other crypto reddit communities that will create synergy between us all (hopefully). it is operating based on information and mutual building and not so much on advertising.
just be careful = ) don't post anything on another subreddit that you wouldn't want them to post on ours.