Some content curation tools have great built in aggregation, and some make it easy to share across different platforms. 

Pearltrees features automated sharing on Facebook and Twitter, bookmarklet extension to make it easier to curate content you come across on the web, and you can visually organize your collections.

Scoop.it's built in content aggregator searches through tons of sources everyday. It also has a bookmarklet so you can curate, or "scoop," webpages. The free version of Scoop.it allows you to curate up to 5 topics and easily share "scooped" stories on Facebook, Tumblr, Wordpress, and other sites. 

Don't overlook Pinterest's pinboards or applications like Tweetdeck for Twitter based curation.

Web Advantage has curated a list of over 30 content curation tools, compare features and sign up for a service.

What service, or services are you going to be begin with?