The ODP (Open Directory Project, also often called DMOZ), is an open content directory that is edited and maintained by approximately 10,000 active volunteer editors. The ODP feeds the directories of Google, AOL Search, AltaVista and other major search engines, and an inclusion in the ODP has long been seen as a good way to secure a Google listing.
The Open Directory Project content is freely available for use on third party websites as long as certain license and attribution requirements are met. In practice, ODP data can also be used to boost a website’s content about a certain topic and artificially inflate a site’s ranking – in other words, it could be used as part of search engine spamming activities.
A recent thread at WebmasterWorld has unveiled that sites using cloned ODP data are apparently actively being banned by search engines. The survey quoted on WebmasterWorld indicated that around 50% of published sites using data cloned from the ODP are not listed in at least one of the three major search engines (Google, Yahoo! and MSN). According to the survey, Google banned around 37% of sites known to use ODP data.
There is no information about the scientific approach and validity of the survey available, but these findings are supported by the fact that search engines are known to penalize the unacceptable use of duplicate content. While there might have been other factors impacting on these sites getting banned, duplicating content (from the ODP or any other source) to try and improve rankings is risky and not recommended.