Maybe when you visit a blog, there are some social bookmarking widgets under the title of the post or at the end of the post (ie in the footer). If you do not already know about social bookmarking buttons, you can visit Social Bookmarking Widget Provider. Now how do you enter this key in the template under the posts. Well it was easy just follow these steps:
1. Visit Addthis.com to register.
2. Fill in the required data and click create account
3. Click Get Your Button.
4. Please select the HTML code and copy it.
5. Login to blogger.
6. Click Design and click edit HTML
7. Click on expand widget templates
8. Find this code: <b:includable id='post' var='post'> and paste the social bookmarking code below.
9. Save your template and see the results .....
Good luck!
http://templatetrick.blogspot.com/