Bodmov,

Yes tags have benefits for SEO and are often used by search engines to index content. They are also helpful for users to connect with other relevant articles on your site. Categories are also important as these appear in your URL’s (if you have that enabled). You can experiment with keywords as categories to increase your visibility in search.

Here is a great post on WP tags,

What Are WordPress Tags and Why Use Them? | iThemes

Best,

Shawn

Categories and tags are WordPress' filing system and you can use them to optimise your site if you're disciplined and organised.

This article describes how I have evolved the way I use them over the years:

Optimise WordPress with Categories and Tags

Cheers,

Martin.

Now i am confused

some say Noindex for them and in other posts say index them benefit to seo

Consider a silo site strategy (you can find more info here in the forums) where you very deliberately link to other pages on your site that are closely related. So you have a site to make money and you structure it like this:

Make Money
Make Money Online
Make Money Online Selling Advertising
Make Money Online Using Banner Ads
Make Money Offline
Make Money Offline Selling Stuff

Whatever . . . In a silo strategy, you would link between all of the make money online posts but not between make money online and make money offline. Those are two separate concepts and you're keeping them separate by (in part) not inter-linking them. This is considered an effective SEO strategy for passing link juice through a site (again, search here in the forums and you'll find a lot of good info).

Contrast that to using a tag cloud. You have links to all of the tags on your site regardless of how closely related they are. This is very much in contrast to the silo strategy.

I would personally never use a tag cloud. You can use tags if it helps you organize. And certainly tags and categories can be used in developing a silo structure. But I don't personally think there's a lot of value to using tags just for the sake of using them - from an SEO perspective.

Also, you should only noindex an internal link if you absolutely do not want it appearing in search results. Like a privacy policy, terms of service, etc. If there's value to someone finding it in search results than do not noindex it. It used to be that you could noindex links on a page to give greater value to other links on that page. But that's no longer the case.

If your blog is in specific niche then you don't need to add category. I have also experienced same thing about tags. .

Tags in Wordpress are really good. I have a blog which I want to rank. I started it's On page Optimization a couple of months back and I have been successful to rank 3-4 pages from the blog. I believe it takes time, but in the end it's worth it.

Tags are good for extra related traffic and also good for seo purpose.

it's true but some say that tags are Low quality pages and consider
duplicate content !

Tags should be "noindex, follow" in wordpress! as they can be a pain considering duplicat content issues.

Google doesn't pay much attention to them anymore, and Categories should always be a priority if you want seach engine rankings.

Tags are great for usability.

Check out this post for in depth wordpress optimization.

Are You Setting Up WordPress For SEO Success? | SEOmoz

try to use some tagclouds and u will be good to go