How on earth do you add a widget?
Fear not! You will not have to try and figure it out, like I had to,
aah and after a very unsuccessful experience with Symphony Widgets I believe that you will find this a much easier experience.
This is a step by step guide how to add a widget from AddThis.
Sign up with AddThis and sign in
Choose your option. I chose "Sharing SideBar"
Follow the prompts
You will taken to the code which you will need to copy
Go to Layout in Blogger
Paste the code which you copied above
View your Blog to ensure that it is what you are wanting
or go back and make the necessary changes.
Now you will have a widget which can help you to promote your site or blog. I hope this was helpful