I would suggest to use systems which could help you to spread posts on other resources. I have plugin for Wordpress, which allows your readers to legally repost your publications to other sites. It allows you to reach new audiences from these sites. Oh, plugin - AtContent, wordpress.org/extend/plugins/atcontent/
You don't need a plugin to make it legal. As long as you give permission (which can be as simple as the text "articles on this site may be posted on other sites, as long as a link to this site is included") it's legal to repost your content. (You don't even need the "as long as ..." part to make it legal, but that's the whole idea.)
Can't agree with you If somebody repost your post - google can bun you or make your search ranking lower. But with AtContent plugin user reposts it like embed code of YouTube video. In this case user gets your content on his/her site and Google track it like legal repost, and instead of restriction for both sites, Google add your site scores in search ranking as an original source. More over, you can block your content on other sites if you don't like it. Sorry for this kind of advertisement, but I just trying to provide you quality answer and information which could be valuable.
You said "which allows your readers to legally repost your publications to other sites". If you give your permission it's legal. Whaty Google or anyone else does doesn't change the legality. Perhaps you meant to say "which allows your readers to repost your publications to other sites without getting penalized by Google". I can't respond to what you meant to say but didn't, only to what you did say.
Rukbat - exactly this "which allows your readers to repost your publications to other sites without getting penalized by Google" - thanks! Did you tried AtContent plugin?
Post regular on your blog, share your blog post on social networking site and also do bookmarking every post