These are most relevant for people who use a CSE over their own blog/site, rather than over other sites which they don't control the markup.
Sorting:
If you have specificd PageMaps, rich-snippets or meta-tags for your posts, you can add them as an option that is available to people who use your custom-search-engine. Do this in CSE by- Enable sorting (www.google.com/cse > Control Panel > Basics)
- Adding the key.