EarthLink has set its sights on helping users squeeze more out of their existing dial-up modems by using caching software.The ISP last week introduced EarthLink Plus, which uses a caching software designed to accelerate the delivery of Web content to individual users.While EarthLink says some users will see data delivered up to five times faster using the EarthLink Plus service, the actual dial-up connection speed will not change.EarthLink is using Propel Software's Web Accelerator tool to boost performance for dial-up users. The software essentially caches Web site content for individual users. The system, in a sense, remembers more information about a Web site, the more often a customer accesses it.Faster dial-up services are likely more attractive to two groups of users: those without broadband service options and those who do not wish to increase their monthly service rates.While it's hard to believe in 2003 that DSL and cable modem services are still not available to everyone, that is still the case. This is especially true for users in rural areas. And there are some users who would rather keep their dial-up service, which in general is $30 less per month than most broadband services.EarthLink Plus lets those without broadband options get more out of their 56K-bit\/sec modem and also let users who want to stick with dial-up get faster service at $29 per month.The EarthLink Plus plan includes eight e-mail boxes, 10M byte of Web space and guaranteed customer service, which guarantees that all calls into Earthlink's technical support line will be answered in five minutes or less.The service does require users have a Windows-based PC.