Is It Important?
Usage of Keywords
So if someone search for "how to get facebook like button" on the Web, search crawlers may not display your post on top of results because they don't care meaning of words and find words which entered into the search engine. So search engine don't know that Facebook social plugins means they include or refers to Facebook like button too. In such a scenario, you can specify keyword 'like button' in the meta tag and then search crawlers will find your post and index to show up on search results by identifying that your post has some information about Facebook like button.
Also you can use long tail keywords in the keywords meta tag. Long tail keywords mean keywords which has multiple words. As for example, think you specify 3 keywords 'Facebook', 'Like', 'Button' or else you can use 'facebook like button' which known as a long tail keyword. Usually long tail keywords have less competition than generic keywords. So proper long tail keywords would generate more traffic for you.
But in Blogger...
Would You Ignore?
4. Click on Edit HTML button.
5. Now add keywords meta tag below with suitable moderations in to your <head> section along with other meta tags.
<meta content='[Keywords]' name='keywords'/>
- URL of Your Page
Add your relevant keywords separated by commas (,) to be affect them on the page you are specifying and it would be better if the content of meta keywords tag would limited to 1500 characters.