The letter "A" on your My Account page is a sign that you are missing a summary on that particular Hub. The summary is what shows up in Google results under your title when someone searches for your Hub. It is a good idea to have a summary that is different than the text in your Hub, e.g., don't just take your first sentence and plug it in for your summary. Your summary should be an accurate explanation of your Hub so a reader from Google would want to click on the link to visit your Hub. While in edit mode, the summary tab can be found on the right hand side of your Hub next to reorder, tags, settings, and group. It is a good idea to go through all of your Hubs that have the "A" and create an original summary.