You are what you read, especially these days. An analysis by media company Starcom Worldwide shows that more people are reading magazines relevant to their particular interests or lifestyle. Using 1998 and 1999 data from Mediamark Research, Starcom analysts discovered that many of the magazines with the greatest gains in readers aged 18 to 49 were niche-oriented titles such as WWF Magazine and 4 Wheeler. Those with the greatest losses were general-interest publications such as Reader's Digest and TV Guide. Of course, these general-interest pubs still command high circulations, but niche titles are chipping away at their readers. Sports Illustrated lost circulation, seemingly at the expense of other titles that focus on individual sports. "Sports-minded readers are still buying magazines but they are seeking titles that address the way they live and the activities they most enjoy," says Kate Lynch, Starcom's senior vice president and global research director.