A web directory or link directory is a directory on the World Wide Web. It specializes in linking to other web sites and categorizing those links.
Directory submission is a process where you submit links pointing to your website on website directories under categories according to the industry. This can be done manually or by using automated software, however, automated software cannot guarantee that submissions are done in the right categories, nor can it determine a quality link directory. The same goes for cheap SEO services that offer submissions in bulk but have no clue which directories are worth linking to. Thus, not identifying quality directories and not completing website submissions manually can lead to a bad link profile.
A web directory is not a search engine and does not display lists of web pages based on keywords; instead, it lists web sites by category and subcategory. Most web directory entries are also not found by web crawlers but by humans. The categorization is usually based on the whole web site rather than one page or a set of keywords, and sites are often limited to inclusion in only a few categories. Web directories often allow site owners to submit their site for inclusion, and have editors review submissions for fitness.
RSS directories are similar to web directories, but contain collections of RSS feeds, instead of links to web sites.