DMOZ, also known as the Open Directory Project, is a directory of websites organized by broad categories that are then organized further by subcategories. Most subcategories are broken down further into more specific categories. Along with the titles of each site listed, there is a short one-sentence neutral description of what each site is about.
The hierarchical nature of DMOZ, as well as the very simple design of the site, makes it very easy to find a collection of sites exactly pertaining to the specific subject you are looking for. The load time of each page is almost instantaneous because of the simple design and also the lack of back ads and java scripts that you find on so many other websites.
You can also use DMOZ's search feature to find what you are looking for in the directory. The top of the search results include the main subcategories related to your search terms followed by a list of individual sites, along with their subcategory. Having the subcategories listed in the search results makes it much easier to find related sites than it is in the big search engines like Google and Bing.
Anyone can submit a website to be included in DMOZ but there is no guarantee that it will be accepted. This is because each submission is personally reviewed by a human editor assigned to that particular subcategory. Editors usually have a special knowledge and/or interest in the subcategory they review.
Because there is a knowledgeable person reviewing each site submitted, only sites with valuable and substantial content get added to DMOZ. For the user searching for information, this makes it easier to find quality sites with usable information instead of having to wade through spammy sites that is so often the case when using a regular search engine like Google or Bing.
There are a few downsides to have all listings reviewed by volunteer human editors. First, it can take a really long time for a site to get reviewed and sometimes sites don't get reviewed at all. Second, there is an element of subjectivity that goes into whether or not some sites get included in DMOZ. For these reasons, on occasion, some very good sites don't get included in DMOZ.
I have seen this in some of the subjects I am most familiar with. On the other hand, the sites that are included are of good quality so you can easily avoid having to wade through lower quality sites and review them yourself before finding high quality sites on the subject you are searching.
Overall, DMOZ is one of my "go to" sites to find information, especially when exploring a new subject. The simplicity of the site makes it really easy and fast to find quality information on the topic you are researching. It would also be a worthwhile volunteer project to commit to if you have a bit of spare time.
There is a link on the homepage that will take you to a form to apply to be a volunteer editor. You can pick your favorite subject(s) and then they ask you to read through the guidelines. You then review a few sites not already in their directory to demonstrate you understand the guidelines.