Once upon a time, it was a good backlinking strategy to create a micro-blog and post links to all your Hubs on it. Tumblr was one place where you could do that.
Google has changed and now, that is not a good backlinking strategy. Google will count only one or two backlinks from it, no matter how many links you create, so it's a waste of time.
If you have a Tumblr blog already and you have lots of friends there, it can be useful to share your Hubs there to get real readers.