Why we need link building?

If your the link exists on their webpages then you don't need to worry just keep on working on directory submissions or social bookmarking sites. If you don't want to pay them then you should go for free and link exchanging services. just update your content regularly, and it makes wondrs.

If you are getting backlinks from high PR sites since long time, then there will not be much effect on your PR. I want to suggest you that when you got good PR then perform Off page optimization for your sites instead of paying for text links.

We have need to build a link that we can increase traffic of site.

I think you will lose some page rank. Why not do SEO yourself? You can build links yourself usinf forum posts, blogs and so on.

[FONT=Arial, sans-serif]Link Building is one of the important ways of improving the rankings of your site in the search engine. This also helps in retaining your ranking. It helps the site in many ways. Through the links you can index the frequent visits to your website. With links, the popularity of your website can increase manifold. With quality links, you will be assured of a good ranking in leading search engines like MSN, Yahoo and Google. The largest benefit from link building is can increase your website traffic.[/FONT]

First mistake stop caring about PR is just a number ....

There are many ways to get permanent backlinks
Dir sub
Articles
Profiles
PR
Blog commenting

I think if such paid backlinks would be dropped after you stop paying then it is undoubtedly that PR suffers. So, trying to building free one-way backlinks using social bookmarking, article submission, forum posting and blogging.

Have a nice day,

we need link building Because of
Links Create Direct Traffic
Links Establish Your Site in 'Communities'
Links Build Search Engine Trust in Your Site
Links Build User Trust in You