Few players in the world of online search are as simultaneously anonymous and controversial as DMOZ, the open directory project. Essentially a human-constructed search engine, DMOZ has made its share of advancements but experts say that it is in danger of slipping into obscurity.

Because of its not-for-profit status and peer-reviewed content, search engine optimization (SEO) professionals can encounter serious issues attempting to place pages on DMOZ. Debra Mastaler, in a guest column at Search Engine Land, writes about a conversation she had with a senior member of DMOZ, who told her that the directory "is not designed to be a site listing service for webmasters."

However, Mastaler also points out that DMOZ might be expanding its local search capabilities, offering opportunities for local businesses to gain search engine optimization (SEO) points by getting listed before that project becomes a reality.

The resources of AOL have been available to DMOZ since the venerable internet giant purchased the directory in 1998 as part of a deal to absorb then-competitor Netscape. Under corporate management, the directory has progressed in fits and starts, and only the fact that its listings are incorporated into Google results keeps it relevant to search engine optimization (SEO).