Your Google+ account is now becoming a part of your identity on the Internet. Since there is no "friend request" as there is on facebook, people wouldn't think twice before adding you to their circle if they found you interesting. This would be a great way for blog writers to improve their readership.
Widget+ allows you to create a customized "Add to circles" blog widget which will link to your Google+ profile. You can choose options to display the number of circles you're a part of, and also it can show your readers, your latest posts on Google+.
You can take a look at the widget at the right sidebar of this blog.