Reddit can be very dodgy, the user base is very averse to advertising of any form and many companies have been burned by going to spammy with it.

That's not to say it can't be done, Moz have a great guide to giving the Reddit crowd what they want here: The Advertiser's Guide To Surviving Reddit - Moz

Personally i'd make a list of forums, social media sites and other stuff related to your niche and build up accounts on them. Not by being spammy but by offering good words of advice, fun stuff and generally helping those forums / networks to become what they want.

These should be enough to curate your blog posts: Twitter, Facebook, LinkedIn, Google+, Stumbleupon, Delicious, Pinterest, FriendFeed, Plurk, Storify, Sulia, BagTheWeb, Bundlr and a few others (all PR10-PR5 social domains).