Even after checking all of the settings, some blogs, with Google+ Comments enabled, may not show the comment form - or may show the form, but comments may not be visible. Besides the visibility of the form, there are other changes which some blog owners don't appreciate.
In many cases, Google+ Comments, like other new features, require an updated post template. This will be seen in blogs with customised post templates, most frequently - although newer, less customised blogs also may need a post template reset.
After getting Google+ Comments working in general, some blog owners find other unexpected changes.
There will be changes seen by the blog owner.
- Almost the entire "Comments" section, in the dashboard Settings - "Posts and comments" wizard, will disappear - though "Comment Location" will remain - and will default to "Embedded". None of these settings are relevant in Google+ Comments. On some blogs, there may be no "Comments" dashboard menu entry at all.
- There are no controls for moderation, or for notification, of comments.
- There is no ability to moderate comments, from the dashboard. Moderation is done under each post, one post at a time.
- As a blog owner, you have no special ability to moderate comments, made against your blog.
- There may be some comments, which you may not be able to moderate - but will publish against your blog.
- If you Block somebody from Following you, that person may still be able to post a Comment on your blog. When you look at the comments, you will only see
This post is hidden because you have blocked the author.
- The "Export blog" wizard, which used to export both comments and posts, will only export posts.
There will be changes seen, by the blog readers.
- People without Google+ accounts won't be able to make - or view - comments (since comments are Circle dependent).
- Visibility of the comment form, as with all embedded comments, is sensitive to cookie / script filters, on the client computers.
- Comments posted outside Google Comments may not be immediately visible, though the comments remain in existence. Resetting various sections of the template may resolve this, when observed.
- If you change the blog address - with either a simple BlogSpot address change, a non BlogSpot address republishing (aka "custom domain"), or export / import - existing Google+ Comments may not remain visible, with the blog. This may be a similar problem, with URLs subject to Country Code Aliasing.
- With a blog using Google+ Comments, the Comments newsfeed will not be published. Any "Recent Comments" gadgets will be useless.
- The comment count, as displayed in the blog main page display, may show "0 comments" - even with comments actually present, and visible when clicking on "0 comments".
- You may or may not get email notification of comments, when comments are not shared specifically with you - even if you own the blog. Other people, who do not own the blog, may get notifications when you do not.
- It appears that Google+ Comments only work with blogs that are published publicly.
There will be problems seen (not seen) by both blog owners and readers.
- With a blog using Google+ Comments, comments made while the blog was using Blogger Comments won't be visible. They will be present, in the Blogger Comments database - they won't be visible, unfortunately.
- With a blog using Blogger Comments, comments made while the blog was using Google+ Comments won't be visible. Google+ Comments will still be out there, in the streams of the owners and readers - they just won't be visible on the blog.
- If you change a blog between Blogger and Google+ Comments, comments made under the previous host won't be visible, to either the owners, or the readers. Neither the Blogger dashboard, or the blog display, supports multiple comment hosts.
Fortunately, in most cases any prematurely made decisions are reversible. Go to the dashboard Google+ menu entry, and unselect "Use Google+ Comments on this blog". The blog will simply return to native Blogger based Comments. Any comments made under Google+ will not be visible to you, from the blog - but everything else should return to normal.
I've now added a Problem Rollup discussion, in Blogger Help Forum: Feature Suggestions and Feedback, where your opinion is appreciated. Please be objective.
See my test blogs Google+ Comments, Dynamic Template Test and Google+ Comments, Simple Template Test if you wish.
Click here, for instructions to revert back to Blogger based comments. Note that you will lose ability to view all Google+ based comments - though the comments will still exist.