digrart

This plugin allows you to add a meta title to each post, page, or custom post type as well as archives and taxonomies directly from the WordPress editor. Simplify SEO for your WordPress site without any extra fluff.

dig Title

Just the Meta Title. / 投稿ページやアーカイブページに、ただメタタイトルを設定できるだけのプラグインです。

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.

dig Title vs MetaTagsFromContent