How far do you go when backlinking...

Hey guys,

I have sites on various profile directories such as Crunch base, and Web Development Sites.

For example http://www.crunchbase.com/company/appsbar-inc is page rank 1, would building links to this via comment linking build its juice pass?

Normally I use article directories to pass juice to mine but its having alittle effect, considering all options.

Would the same work on web-directories if the site is hosted on its own unique page.. or does this give little effect?

Thanks

Yeh, blasting it with blog comments should be fine. I'd start with small tests and then scale up just to be sure it works for you.