You should use a link redirect script for any of the following:
- You want to track the clicks in your server logs
- Search engines don't want to see the links because they are paid
- You don't want the sites you are linking to to rank better because you link to them
Link redirectors are most commonly used for advertising. In that case tracking is essential for payments and Google requires that the links not pass Pagerank. Link redirector scripts are not the only method that can be used in this case. using rel=nofollow
on the links prevents pagerank passing and clicks can be tracked using JavaScript and analytics packages.
If you are linking to a competitor, you could consider using a redirector script or rel=nofollow
.
Beyond these use cases, I see little value in redirector scripts. They won't conserve link juice on your site. Google's Pagerank algorithm now drops link value equally for plain links, nofollow links, and links blocked by robots.txt
MediaFire and Google drive links are fine to let search engines crawl. They are not sponsored, and having the links on your site won't hurt your rankings in any way.