Not sure about types of backlinks...

So I'm on ahrefs looking at my backlink profile, and I see this category with the following items:
- Text
- Redirect
- Frame
- Form

A few questions:

- Redirect link: is this when you purchase a domain and just set it up to redirect to your site? Or is it a PHP redirect that they're talking about?

- What exactly is a "form" backlink? I've been racking my brains but I have no idea.

- How important is it to diversify all of these? Is there a general guideline for what percentage of your links should be text/redirect/frame/form?

Thanks!

I am guessing that they probably misspelled "Forum" for form.

don't concentrate on that reports!just concentrate on high quality link building!

301 redirect can be done with htaccess and PHP as well.

form link, probably means the url you send somebody to when they submit a form. The url in the action attribute.

and dont use ahrefs, majestic has better crawlers in my experience and catches more backlinks sooner.

Not Forum, but Form Backlink.. Good question, im also blur in what was Form backlink..