recently i did many backlinks for my site,but its pr down,i m very confused,pls check my site www.agoodic.com , help me,
why?
Make sure the backlinks are from reputable sites that have similar content. Otherwise you could be shooting yourself in the foot.
If you can compete and win to show your site on the first page of google search then dont bother for your PR value whatever it is. As well good PR is sign of better search position.
Always remember to link with related - same content websites.
Again, try to add minimum 1 page every day , if you want to do well with page rank.
there a re lots of reasons why your pr went down one reason is you might be lionking to bad neighboorhood better check your link partner
There are probably many reasons why your pr went down.
Maybe you are linking to bad neighbors.
Maybe your competitors are doing better job than you.
Maybe you are not linking to relevant sites.
All is possible, just check carefully and keep on working.
Nobody can tell you exactly why apart from Google, just carry on building some backlinks and working on your websites SEO, that would at least be my advice, look to build high pagerank dofollow backlinks, they are the best way to increase pagerank.
I think, pr is all about quality inbound links. You might have a lot of backlinks but does these inbound links do have quality? The sites that are linked to you must have high pr too and must be related to your site’s niche.
its not just the number of backlinks… relevancy and quality are also a big factors…
Kind of off topic: but I just read today that Google is now taking into account page load time in determining rankings. Good news for those interested in clean, semantic code and progressive enhancement. 
Relevancy has NOTHING to do with PR
Google is strict to the backlink. Not all the external links you make for you wensite will be indexed as backlinks. You need promise the quality of external links.
make sure your backlinks relate with your site,and get more high quality backlinks,the quality is better than quantity.
There may be many reasons for your pr going down. Google has it’s own criteria and parameters for giving you the PR and google always its algos time to time.
There may be your back links are coming from the pages which have many outbound link there, links placed on your partner page may be unrelated. the reputation of those sites in google from where you make links for your website.
Hi Buddy!!!
May be your site has got more backlinks by un ethical Google in seo...it will happened.
The way the single digit PR is generated your backlinks can grow and your PR can go down simply because other sites grew by more.