DEAFilter is a free RESTful API that can be implemented into an existing site with a couple lines of code. It is used to get rid of all Disposable Email Address services that are used to infest a site with fake users and spammers.
If you run a website, like many of our readers, and you have an account system, you probably have problems with spam. One of the main sources of spam is users who register using disposable e-mail addresses. These can be generated by spammers programatically, using services like the Guerilla Mail API I covered previously, and used to make tons of accounts to try to get blog spam through. If this is a problem for you, the DEA Filter API can help.