CAcert has tried for some time to provide free X.509 certificates based on automatic checks and a web of trust. They never managed to get the root certificate included in the default installations of the major browsers. As I read it, they’ve given up on Mozilla for now.
Aaron forwarded me a link to a blog post by StartCom where they announce that their CA will be included in IE soon. As they are already recognized by Mozilla and Safari, their certs are pretty much as good as any other commercial x.509 cert for servers.
In that respect, they are not unique, you can buy commercial grade certs from various sources, the most popular being Thawte, Equifax, Usertrust, Comodo, and Verisign.
What makes StartCom special is the fact that they give away free certificates similar to what CAcert is doing. Their enrollment at http://www.startssl.com/ is pretty much straight forward and getting certificates (both by uploading CSRs or by letting them generate a key) is painless.
Furthermore, they impressed me by:
- Adding priv.at as a valid domain suffix within a few hour after I mailed them.
- Checking the server for which you requested a cert and giving you hints if you made a configuration mistake.