Online directories are a great way to make a particular type of content more discoverable or target a very specific niche. Search engines are great but their generalisation makes them difficult to use as tools when you're looking for a specific type of content. It leaves room for many online directories that are laser focused. Product Hunt is a directory of products, PodBean is a directory of podcasts, and there are directories for marketing tools, code libraries, and more.
Since they naturally align with the functionality of search engines, search can also be a major driver of traffic to these sites. When I first built InboxReads I knew the goal was to help people find newsletters and search engines are usually the first destination for finding those. It's a perfect match of marketing channel and product.
Today 60-70% of InboxReads' traffic comes from organic search and it's commonly on the first page when searching for specific types of newsletters. I did this by following all the basic recommendations you'll find online to get your pages indexed and ranked highly. But there are a few ideas I stole from similar sites and less common tips that have had a huge impact and are especially relevant for online directories.
This is a trick I picked up from Nomad List. If you go to the Nomad List home page and select some filters you'll see the page URL changes to match those filters. The URL doesn't just use query parameters or a hierarchical format. It's actually a piece of descriptive text about the page that includes the filters.
Instead of creating a URL like /places/cold?month=february it creates a readable URL. A readable URL has the advantage of being accessible to humans and algorithms alike. How much it affects your rankings is hard to say but the increased accessibility to humans can increase clicks to your site.
I used the same technique for InboxReads and it now has its own Quick Answer box for some queries with a readable breadcrumb display of the URL. For more URL structure tips check out this guide by Moz.
A canonical link element is an HTML element that helps webmasters prevent duplicate content issues in search engine optimization by specifying the "canonical" or "preferred" version of a web page.
It's easier than you think for different versions of the same page to be indexed by Google and negatively affect your rankings. HTTPs and plain HTTP pages can be indexed separately. URLs with slashes at the end and without as well. Even the case of your characters can have an effect.
It's important to include the canonical link tag to tell search engines what the preferred format of your URL for a specific page is so only that version is indexed. You can also create 301 redirects from an unwanted variation of your URL to the correct one.
Every bit of content on your site has the potential to be useful for someone searching. Often there are surprising ways you can create useful pages that repurpose existing content while still being valuable to visitors.
One example is by making your search filters into unique pages. For InboxReads, newsletters can be filtered by the rate they're sent at (daily, weekly, monthly, etc.). Rather than have the filter be done purely on the frontend I let each filter correspond to a specific URL that can be indexed by search engines. You can find tech newsletters here but also daily and monthly tech newsletters on their own pages. This means people searching for newsletters sent specifically at those rates will find a useful page that lists exactly that.
This can be expanded to use every tag you apply to every bit of content. Marketing Examples has an in-depth look at how Nomad List does this.
Internal links are important for search engines to find all the content on your site. Some pieces of content might only be accessible through search which web crawlers rarely index. Instead, you can tie content together by displaying related content on a page.
On every newsletter page on InboxReads the sidebar displays a handful of related newsletters. What's displayed is based on the tags of the main newsletter. It's valuable to users but also allows rarely seen newsletters to be indexed by search engines.
This can also be used to show different types of content that are also related. You can add blog posts, videos, and anything else that might be related to the main content. It's a great way to increase your internal links while still offering value to users.
I'm sure there are a lot more tips that are specific to directory-type sites. What are some you've found that have proved successful?