Cloudster is a great domain name for any type of Cloud or SaaS based business. Cloud and Software as a Service is hugely popular in the industry at the moment. Almost everything from email to transportation to billing or even tax filing is available as a cloud service. This .biz TLD is a memorable name with Cloud as a prefix would make a great brand for any type cloud business.
Great news! Domain Cloudster.biz has been registered in the past and previous domain owner(s) may have forgot to renew or dropped it.