When you write on your blog whether you are just expressing your views or giving useful information to people, you are participating in a creative act and creating something unique.And as such would like to let people know what they can do with your content and how you would like it to be used.Hence comes the need to apply a license to your blog which states explicitly what rights you grant to another person regarding the usage of your blog content.
With regard to licenses, there are basically three approaches
1.CopyRight 2.CopyLeft 3.CopyME
1.Copyright:Yeah ,who hasn’t heard of this .Basically says that whats mine is mine and you’re not even allowed to come close to it, except if you pay me of course.To implement this method of copyright , all you gotta do is put a footer or label saying that stupid line-‘All Rights Reserved’. Not a very effective method of copyright and downright so for the internet . It just doesnt work here coz people are gonna copy text from your blog, link to it , discuss it and comment upon it while you keep saying that they gotta ask you first.

2.Copyleft:This word is just a parody of copyright but represents the class of licenses that allow you to use content but in a restricted and pre-decided manner.This is the type of license that is most commonly used on the internet.If you wanna use this method of licensing for your blog, then check out the following licenses.
CreativeCommons:This is a set of licenses which basically allow people to use your content as long they attribute it to you.It is a nothing but a form of lesser form of copyright and is accused of being more in favour of the content developers.The above link will take you to the creative commons license generator page and after a few questions will give you a badge you can put up on your blog.
GNU FreeDocumentationLicense:(GFDL):This is basically a license giving readers the rights to copy, redistribute, and modify a work and requires all copies and derivatives to be available under the same license.Many people do not like the fact that derivative works also have to have the same license but I think this is fair coz if i gave it to you free , then why shouldn’t you give away it for free.The above link is to a footer which you can put up on your blog .Alternative you can just put up the image.
However,this may not apply if someone has taken your content and made something much better out of it.Hence, we have what are called strong and weak copyleft licenses.
FreeBSD License: Similar to the GFDL except that it doesnt require derivative works to bear the same license and giving people greater freedom to use your work.
3.CopyMe:This is a new concept which says that copyright is totally flawed and should be abolished.One implementation of this method of licensing is Kopimi.
Kopimi:When you use this license, you’re not just allowing people to copy your work but requesting them to do as much as they like in any manner whatsoever.This means no attributions, no restrictions,no legal bullshit.Take it and do what you want with it.You can apply this license by putting up the Kopimi logo’s in your blog.
Comment:Here’s a list of published by GNU of all the licenses for documnetation that are available