Question about URL shortners, blacklists and link juice ..
 

Over the last couple of years, we seeded the internet with about 3.5 million different short URLs using our own URL shortener. We are now thinking about redirecting all the urls to one or more other websites.

Any reason a sudden change (redirect) would raise a flag that would cause the new receiving website to the blacklisted?

What link juice value is there when the url is run through a url shortner?

Google frowns upon anything a stupid person wouldn't do :2 cents:

use this code in a URL mapping script,
in url batches of 100

It will take 5 - 8 years to finish and no one will notice the 301 attack :)
if you reboot you will have to reset the bash script's read file

I'm not a coder, but from the looks of it, along with your comment, it appears to help drip feed the changed urls over a period that in the internet world is basically "forever". :winkwink:

Nalem, earlier this week Google announced that 30X redirects do not waste pagerank anymore.
Also, if redirecting to irrelevant destinations, it may be that Google will see that as soft 404.

So, if you're redireting from a page about cars to a page about cats, or you redirect a content page to a homepage, you should think twice.