Dell has agreed to buy EMC Corporation for a deal worth $67 billion. While EMC isn't a household name, some of its products and subsidiaries are. In addition to selling cloud services, storage and analytic solutions to enterprise companies, EMC owns the security firm RSA and the virtualization solution VMware. The deal is huge -- it's being billed as the largest tech acquisition in history. EMC is probably worth twice as much as Dell itself right now, and has some 70,000 employees worldwide.