What are googles restrictions on obtain page ranks

Hi,

I have a link exchange system and would like to be able to display users page ranks. I understand that there are some limits and restrictions.

What are the limits and restrictions on getting page ranks?

 

There are many page rank tools which display page rank of a website, so I guess there are not much restrictions.

 

Yes, I agree.
many tools could display pagerank

 

here are many tools which can show the page rank i think there is nothing like restriction word to show page rank on your site.

 

i dont think there are restrictions for page rank