on Thursday plans to announce it has commissioned Agents Inc., Cambridge, Mass., an MIT Media Lab startup, to create its Web site. Agents Inc. is the creator of Firefly
, an experimental Web site that uses intelligent agent technology to learn about users' preferences in music, movies and books and make recommendations about other music. Rolling Stone has had a presence on CompuServe for a few years, but has lagged in getting on the Web. The site is expected to launch later this spring.