Posts across Kinja have an option labeled Share to Kinja which allows you to share a post to a blog where you are an author.
After clicking the share option, a preview of how your share will appear on the homepage is loaded. To share the post normally, select your desired blog and hit share - simple.
The share unit also allows you to scheduled a share. Click the Schedule option and choose you desired date and time. Once you've made these changes, choose your destination blog and hit the schedule button. Scheduled shares can be found on the drafts page of the blog you shared to.
After sharing, the original post will appear on the chosen destination blog's front page, but the post permalink will direct back to the original blog.
You can also share a post to Twitter and Facebook by clicking either service's logo at the bottom of a story page. This will create a new post or tweet on your chosen service - after you've signed in with the appropriate account credentials - with a summary and link to the shared content.