Timo Schlueter

TagMeta generates meta keywords using your most used tags. 
It automatically gets the 10 most used tags out of your 
blog posts and pages and puts them into a valid meta- 
keyword string. This string then appears in the header of 
the home page of your theme. If you want to add tags per 
post, i suggest youre going to use the Headspace plugin.

TagMeta

TagMeta generates meta keywords using your most used tags.

hitmax1978

Find the post. Click “Edit post”. Activate the “Text” tab of your post.
To modify the title tag of your post, add a simple string into your post content: 
<!—title=”your title”—> (See screenshot-1)
To modify the description tag of your post, add: 
<!—description=”your description”—> (See screenshot-1)
IMPORTANT!!! Be sure after “<!” characters you have two “-” characters. It is similar to HTML comment tag.
Multilingual support
If some kind of multilingual plugins are active (for example Multilanguage by BestWebSoft) – you can define titles and descriptions in other way: (See screenshot-2)
English locale (United States) 
<!—title_en_US=”your title”—> 
<!—description_en_US=”your description”—>
Українська локаль 
<!—title_uk=”Ваш заголовок”—> 
<!—description_uk=”Ваш опис”—>
Русская локаль 
<!—title_ru_RU=»Ваш заголовок»—> 
<!—description_ru_RU=»Ваше описание»—>
Feedbacks are welcome. Visit <a href="http://onlineservicetools.com/meta-tags-from-content-wp-plugin-discussion-feedbacks" rel="nofollow ugc">onlineservicetools.com</a>

MetaTagsFromContent

Good in multilingual site

Generates title and description tags from post's content.

TagMeta vs MetaTagsFromContent