See www.zabbix.com for the official Zabbix site.
Zabbix.org is the umbrella for allowing the community to become more engaged in Zabbix. Tools such as translation, source control, wiki, and question/answer are some of the ones which will be available here.
Does that mean zabbix.com will become more closed?
No, Zabbix is still and will continue to be released under a Open Source Licence.
Sounds neat, how do I get involved?
Right now most of the conversations regarding Zabbix.org are occurring on IRC. Come join us on #zabbix on freenode.