Robots Tags

Below are the robots tags headers that you can use.

Tag	Meaning
all	There are no restrictions for indexing or serving. This is default for all pages
noindex	Do not show this page in search results and do not show a "Cached" link in search results.
nofollow	Do not follow the links on this page
none	Equivalent to noindex, nofollow
noarchive	Do not show a "Cached" link in search results.
nosnippet	Do not show a snippet in the search results for this page
noodp	Do not use metadata from the Open Directory project (DMOZ) for titles or snippets shown for this page.
notranslate	Do not offer translation of this page in other languages in search results.
noimageindex	Do not index images on this page.
unavailable_after: [RFC-850 date/time]	Do not show this page in search results after the specified date/time. The date/time must be specified in the RFC 850 format. Example: 17 May 2012 15:00:00 PST

The only tags which you should focus on are noimageindex, noindex and nofollow. Rest are just not required for a small scale blog. All of these tags are useful when you have a corporate blog or website with thousands of pages or even millions of pages. They help to control how search engines may crawl your content.


When to use noimageindex ?
If you are sharing personal or family pictures on any of your posts or page then may be you would prefer not to make those pictures public and keep them limited to readers reach only. In such case you may check this option and robots will be directed not to index the pics or images used inside the post.


When to use noindex?
Any page or post that you want to hide from robots and visitors can be tagged as noindex. Visitors wont be able to discover that page via search engines or may be even with the Google Custom Search Engine.
You can even noindex post or pages that you think will effect your search ranking. Google Panda Effects all those blogs which publishes low quality content. If you feel any of your post is just for entertainment purpose and does not relate to your niche then you can simply choose the noindex option from Header Tags.


When to use nofollow?
If you are creating a useful directory of 100 or more links that all point to some external websites and you don't want to pass your PageRank juice to them then you can choose the nofollow header tag.

Source: Settings For "Custom Robots Tags" Inside Post Editor | My Blogger Tricks