IaaS, SaaS and PaaS are the obvious as-a-service offerings, but there are plenty of others. In fact, just about every letter of the alphabet has an "as a service."TIPS: How to become SaaS savvyAAccess as a serviceAccess as a service, or AaaS, is related to cloud security and specifically how users gain access to it, Access-smart.com explains.AaaS can also mean authentication as a service, which also refers to cloud security, and a single- or two-factor authentication system to access cloud data.BBackup as a serviceBusinesses such as Symantec and Verizon allow service providers to offer backup as a service.CCompute as a serviceAT&T offers compute as a service, meaning computing capacity on an as-needed basis for enterprises.DDatabase as a serviceForrester noted the term in a 2008 report.It can also mean desktop as a service, which Dell offers.EEmail as a serviceAlso known as webmail, of course, the federal government experimented with using the term.EaaS can also refer everything as a service, which is how HP describes its cloud strategy.FFirewall as a serviceCoined to describe cloud security, as the Trend Cloud Security blog explains.GGoogle platform as a serviceZDNet has a reference guide for the difference between the Google PaaS and Amazon's model.HHardware as a serviceAn early term for infrastructure as a service, now offered by providers such as AWS. Some providers still use the term, though, such as Skyrope and Equus.IInfrastructure as a serviceA variety of providers use the term IaaS.JJava platform as a serviceA type of application development, as IBM describes here.KKnowledge as a serviceUsed to describe a crowd-sourcing model, as Silicon Republic blog describes. Salesforce.com, the major SaaS provider, also describes KaaS in its cloud offering.LLog on as a serviceLog on as a service can either refer to a Windows command or it can refer to cloud security.MManagement as a serviceManagement as a service can take many forms, including cloud security, as described by Verizon.Also, you might see marketing as a service, which is just that, explains the CRM Search blog.MAAS CONFUSION: "As-a-service" gets out of handNNetwork as a serviceCisco used the term to describe its open stack offering.OOpen platform as a serviceOpen platform as a service is a way to describe PaaS offerings that are open source, as described here.PPlatform as a serviceUsed to describe a cloud-based application development and testing model.QQuery as a Web serviceA product by SAP used by business enterprises.RRobot as a serviceRaaS is a term used by Intel in a white paper to describe service-oriented robotics computing.SSoftware as a serviceA widely used term to describe cloud-based software that is accessed via the network.TTesting as a serviceHP offers testing as a service for application developers to test their research.UUser interface as a serviceSalesforce.com announced in 2007 its user interface as a service model, which it describes here.VVideo surveillance as a serviceVideo surveillance as a service is an emerging trend in the SaaS market, as a CSO report explains.WWebsite as a serviceA number of providers offer website as a service.XX as a serviceAs the blog SearchCloudComputing.com describes it, XaaS means anything as a service.YYou as a serviceAs this study points out, a variety of cloud-based initiatives can be classified as you as a service.ZZebra as a serviceNot yet an enterprise IT term, sales firm Selling to Zebras is attempting to make it one.(Note: This list is not meant to be all-inclusive; if you have suggested additions to the list, send them to BButler@nww.com.)Network World staff writer Brandon Butler covers cloud computing and social media. He can be reached at BButler@nww.com and found on Twitter at @BButlerNWW.