This category is for computer companies that have products (usually with a significant hardware component) that are solely related to data warehousing. This would include data warehouse appliance companies as well as specialty storage vendors.
Companies offering database or database related software are generally listed under Computers/Software/Databases or its subcategory Computers/Software/Databases/Data_Warehousing.
Companies maintaining mailing lists or engaged in direct marketing are not listed here. Consider submitting somewhere under Business/Marketing_and_Advertising/Direct_Marketing .
Companies archiving data (e.g. to tape or CDROM) or offering other backup solutions are listed under
Computers/Hardware/Storage or Computers/Software/Backup