Google+ allows you to disable comments and lock your posts, and you can do so even before sharing to the Google+ stream. These features work on per post basis, meaning (if you want to) you need to apply them every time you post. Disabling comments prevent others from leaving comments on a post (duh!), while locking post prevents them from re-sharing it or mention people you haven't shared it with.
I’m sure these two privacy features will come in handy at one time or another, so let’s learn how to use it:
- Click on the Share what’s new… box and enter your post. Once clicked, a box (share box) will appear below the post box.
- To access the options, click on the down arrow tip located on the right of the share box.
- A dropdown should appear, with Disable comments and Lock this post listed. Click your selection.
- Finally, click Share button to publish.
Here’s a video by a Google engineer to go with that (sourced here):