AOL for DOS was launched using a GeoWorks interface followed a year later by AOL for Windows. This coincided with growth in pay-based online services, like Prodigy, CompuServe, and GEnie. 1991 also saw the introduction of an original Dungeons & Dragons title called Neverwinter Nights from Stormfront Studios; which was one of the first Multiplayer Online Role Playing Games to depict the adventure with graphics instead of text. During the early 1990s, the average subscription lasted for about 25 months and accounted for $350 in total revenue. Advertisements invited modem owners to "Try America Online FREE", promising free software and trial membership. AOL discontinued Q-Link and PC Link in late 1994. In September 1993, AOL added Usenet access to its features. This is commonly referred to as the "Eternal September", as Usenet's cycle of new users was previously dominated by smaller numbers of college and university freshmen gaining access in September and taking a few weeks to acclimate. This also coincided with a new "carpet bombing" marketing campaign by CMO Jan Brandt to distribute as many free trial AOL trial disks as possible through nonconventional distribution partners. At one point, 50% of the CDs produced worldwide had an AOL logo. AOL quickly surpassed GEnie, and by the mid-1990s, it passed Prodigy (which for several years allowed AOL advertising) and CompuServe. In November 1994, AOL purchased Booklink for its web browser, to give its users web access. In 1996, AOL replaced Booklink with a browser based on Internet Explorer, allegedly in exchange for inclusion of AOL in Windows. AOL launched services with the National Education Association, the American Federation of Teachers, National Geographic, the Smithsonian Institution, the Library of Congress, Pearson, Scholastic, ASCD, NSBA, NCTE, Discovery Networks, Turner Education Services (CNN Newsroom), NPR, The Princeton Review, Stanley Kaplan, Barron's, Highlights for Kids, the U.S. Department of Education, and many other education providers. AOL offered the first real-time homework help service (the Teacher Pager—1990; prior to this, AOL provided homework help bulletin boards), the first service by children, for children (Kids Only Online, 1991), the first online service for parents (the Parents Information Network, 1991), the first online courses (1988), the first omnibus service for teachers (the Teachers' Information Network, 1990), the first online exhibit (Library of Congress, 1991), the first parental controls, and many other online education firsts. AOL purchased search engine WebCrawler in 1995, but sold it to Excite the