Sorry to jump on your thread but if I understand your request, you can actually do this now.
Just to be sure, I believe you want to be able to schedule a message, photo, video, etc. to post on your various social networks but don’t want that message(s) to display on your blog/website. If that’s what you’re trying to do, as I stated you can do it now.
Here how I do it.
1. Create a new custom post type but do not make the post public, searchable, or archived. There are plugins to create custom post types but it only requires a few simple lines of code added to your theme’s functions.php file (if you need help with this let me know)
2. Then in the SNAP settings, add the custom post type you create as one of the post types that get autoposted.
3. Simply add your post, image, video, etc. and schedule the post using the built in WP post schedule function.
4. [Optional] You can customize the SNAP autopost setting per each post as you normally in the SNAP metabox under the post editor.
Your post will be sent out as SNAP normally does but will not be visible or searchable on the frontend of your website.
If you’re concerned about your website database or Google finding your new custom posts (which you can block using a robots.txt file), you can use a plugin like Post Expirator which can unpublish or delete your post after a certain date.
This functionality can get very advanced. With a few additional plugins or customizations, you can create everything from a poor man’s Hootsuite (schedule bulk autopost in advance & pull in RSS feeds from any source to post to your personal and/or business accounts) to a complete Private Blog Network for SEO purposes.
Whenever, SNAP v4 comes out (which I hope will be soon because it’s been almost a year since the first announcement and still no beta) the above will be even more powerful because of the ability to auto repost specific types of post and categories.
Hope this helps.