The domain authority on expired domains comes mostly from the inbound links to their deep pages. If you have similar enough content that your domain can satisfy the users that click on those links then you might get some SEO benefit from the domain redirect. To get it, you would have to put appropriate redirects in place.
For example if you find a link to:
you could redirect it to your blue widgets page:
It wouldn't work to:
- Redirect it to
mysite.example.com/blog/the-wonders-of-blue-widgets and give users a 404 error
- Redirect it to your home page:
mysite.example.com/ which Google would view as a "soft 404" and not give the link any credit
- Redirect it to an unrelated page such as
mysite.example.com/red-filanges (which wouldn't satisfy visitors).
If the links to the expired domains are spammy or paid, redirecting the expired domains to your site would hurt your rankings. It would be likely that Google would penalize your site.