Footer links are last-resort navigation
Your footer is not a second chance at navigation. It's a place to put things that didn't earn a spot in the primary menu but still need to exist somewhere.
Most sites treat footers like a dumping ground for every link that someone once insisted was important. Legal pages, social icons, site maps, contact forms, newsletter signups, secondary services, partner logos, and a duplicate of the main nav "just in case." The result is a wall of links nobody uses except people who've already given up looking anywhere else.
What actually belongs in a footer
Legal requirements: privacy policy, terms, accessibility statement. Contact information if your site doesn't have a dedicated contact page in the main nav. Copyright and basic organizational identity. Maybe — maybe — a small set of links to genuinely secondary content that a fraction of users will need occasionally.
That's it. If you're putting your core service pages in the footer because they "didn't fit" in the top nav, your information architecture is broken higher up.
The newsletter signup problem
Newsletters in footers perform poorly because footers are where attention goes to die. If your newsletter matters, give it a dedicated page and link to it like you mean it. Or put a single-field signup in your sidebar. Or don't have a newsletter.
Sticking a signup form in the footer and then wondering why conversions are low is like putting your best product on the bottom shelf behind the clearance bin.
Footer nav that duplicates main nav
This convention survives because someone once said it improves SEO. It doesn't. It just makes your footer longer and gives you twice as many navigation labels to keep consistent when you rename something.
If users are scrolling to the footer to find primary navigation, they already tried the top of the page and failed. Fix the thing they tried first.
Social icons no one clicks
Every site has them. Almost no one uses them. If your social presence actually drives traffic or builds community, link to it from a place people look at. If it doesn't, admit that the icons are there because you think they're supposed to be, and delete them.
What good footers do
They're short. They answer the question "who runs this site and how do I contact them if something's broken." They provide the legally required links without pretending those links are interesting. They don't try to be a secondary homepage.
A footer is the period at the end of the page. It doesn't need to be a whole new paragraph.