Flickr is a popular photo-sharing service by Yahoo. It allows you to backup photos & videos to access them from anywhere on any smartphone, computer or tablet. Flickr allows you to add comments on other users photos and videos. Also, you can allow any other Flickr user to comment on your photos and videos. You can specify default settings for comments. You can decide that who can view your photos and videos or who can comment on your photos and videos by simply editing your settings. If someone leaves a comment which you don't like, then you can delete it. You can also block a person from commenting on your photos and videos.
You can install PicBackMan's Flickr uploader for Mac from the website to ensure your photos never go missing and they are safely backed up.