Leaving a Comment
If you decide to comment on a Google search result, your comments are public. If you decide to need to delete a comment, click the "Edit" button next to the comment you've made. You'll have the option to simply edit the comment or delete it all together.
Find All Your Comments
If you'd like to view all your comment activity, scroll to the bottom of your Google search results page. You'll see a text link that says "See All My SearchWiki Notes". From here, you'll be able to see all the comments you've made, as well as all the search results you've voted up or down.