How to know if a backlink is valid?

I am hiring someone to build backlinks for my website. And need to know whether the backlinks are valid.

I am thinking of the following criteria:

1. The webpage containing the backlink is cached by Google.

2. The webpage containing the backlink has a PR0+

3. The backlink can be found in Google Webmaster Tools(http://www.google.com/webmasters/tools/)

4. The backlink can be found in Yahoo SIte Explorer(http://siteexplorer.search.yahoo.com/)

5. The backlink can be found in third party link checker tools such as http://check-backlink.com/cgi-bin/bl_checker.pl

Just wonder which criteria should be the right one to check the validness of the backlinks for my website?

Thanks

 

Eventually 'most' backlinks get spidered by google, so in the long run they should all be valid,

 

Just check these thing in links -
- Relevant
- PR0+
- Less OBL
- Old Domain
- Home page PR2+
- SEO Friendly site etc.

 

I am sorry, you can not evaluate the links in the manner you have listed. Instead please look into them manually and have them checked for dofollow by seo firefox addon. This is the best method among any.

 

Pretty good point. I don't imagine the site really has to be SEO friendly - just friendly enough to get crawled to where the link is at

 

That would be the big one for me. After the work is done I'd give it about two weeks to see if the source of the backlink is cached (backlinks could be placed on new pages not yet cached or old pages that need to get re-cached with your link).

 

Webmaster tools is not an accurate indication of how many back links point to a site. Webmaster Tools only gives a sampling of links and it shows links that don't pass PR as well as ones that do. The link: command in Google is also virtually useless. SEOMoz did a good post talking about this issue here http://www.seomoz.org/blog/google-link-command-busting-the-myths