How should I give URL to my social accounts on my web page, to make perfect SEO?
with nofollow attribute as like this?
<a href='http://www.facebook.com/example' rel='nofollow'>
We Are In Facebook!</a>
without nofollow attribute as like this?
<a href='http://www.facebook.com/example'>
We Are In Facebook!</a>
or with a redirect as like this?
<a href='http://www.example.com/redirect.php?url=http://www.face
book.com/example'>We Are In Facebook!</a>
For trusted sites such as Facebook, the link structure you use will not affect the SEO of your website at all. There is a small chance that allowing the follow will help your page on Facebook.
When you link to content, you are telling Google, "I trust this page." If you have a habit of trusting crappy pages, then Google thinks you have bad taste in friends and further assumes that your own content is sub-par, hence lowering your ranking. Therefore, if you don't want to vouch for a particular link, use nofollow.
Google has a nice video and page that explains much of its logic and provides some specific examples.
A plain link is fine:
<a href='http://www.facebook.com/example'>
We Are In Facebook!</a>
None of the testing that I've done indicates that linking to other relevant, non-spammy sites effects rankings either positively or negatively.
rel=me links need to be bi-directional to be properly implemented. There isn't a way to get Facebook to add the rel=me attribute to the return link, so using it just in one direction seems pointless. "Me" also indicates "personal." Corporate websites would be unlikely to use it for that reason.
