With the series finale of its marquee show ''Dawson's Creek'' tonight, the WB will be left without one of the two programs that established the 8-year-old network as a destination for young viewers. The other, ''Buffy the Vampire Slayer,'' moved to UPN in 2001.

But the WB isn't skipping a beat. Unlike many of its broadcast competitors, the youth-oriented network has excelled at generating new shows its audiences like, including ''Smallville,'' ''Gilmore Girls,'' and ''Everwood,'' while maintaining veteran series such as ''7th Heaven,'' which in its seventh season is the network's No. 2 show.

With its goal of wooing a niche audience of teenage and young-adult viewers with coming-of-age and family-focused stories that reflect their own lives, the WB has become almost like a cable network. Its viewership is relatively low -- it ranks fifth in total viewers among the big six broadcast networks -- but the people who are watching are highly desirable to advertisers, allowing the network to charge aggressive ad rates.

To date this season, the WB has had an average of about 4.1 million viewers during prime time, almost half of whom fall in the category of 12- to 34-year-olds, according to Nielsen Media Research. By comparison, NBC has had an average of about 11.6 million prime-time viewers this season, 3 million in that age category.

''The WB has cornered the market on coming-of-age stories,'' says Victor Strasburger, coauthor of ''Children, Adolescents, & the Media'' and a professor of pediatrics at the University of New Mexico. ''They realize teenagers and young adults are what's happening. Teenagers are an amazingly powerful demographic in terms of purchasing power.''

While ratings for ''Dawson's Creek'' have declined over its five-year run, other WB shows have been on the rise, including the network's No. 1 program, ''Smallville,'' which completes its second season on Tuesday.

The story of Superman's teenage years on earth has drawn an average of 6.6 million viewers per show this season. Executive producer Al Gough says the show is just hitting its stride: ''The question of Season 1 was: `Who am I?' The question this season was: `Where am I from?' Season 3 is going to address `Where am I going?' For Clark [Kent] as a character, what's his next step?''

Gough says a pending ''Superman'' movie by Warner Bros. and DC Comics will not affect his show: ''We have an agreement not to introduce any other Kryptonians, which is fine. We will play out high school for two more years, and then Clark is off to college.''

''Everwood,'' which debuted last fall, has attracted an average of 4.8 million viewers per show this season. The program follows the Brown family after the unexpected death of wife and mother Julia. Andrew, the father (portrayed by Treat Williams), is a prominent New York surgeon who gives up his lucrative practice to move to Everwood, Colo., and raise his children, Ephram, 16 (Gregory Smith), and Delia, 9 (Vivien Cardone), who resented their dad's workaholism.

Creator and executive producer Greg Berlanti says the show has struck a chord, particularly among males. ''A part of the reason is wish fulfillment,'' he says. ''Every guy wishes their father gave up his job for them.'' But while about 33 percent of the audience is male, Berlanti says the majority of his viewers are female teenagers ''who have crushes on Treat and Gregory.''

When the season ends on Monday, the Brown family will have acclimated to Colorado and finished grieving, says Berlanti. Next season, he notes, will focus on new themes: ''Where does happiness exist? Can they find their way back to wholeness? Can Andy be a complete man again? Can all the years that he didn't pay attention to his children be redeemed?''

Yesterday, the WB announced a new batch of shows that will appear in its fall lineup. Most of the comedies are family-focused and fit the WB profile. One exception is the new drama ''Fearless.''

Coproduced by Jerry Bruckheimer, ''Fearless'' is a crime drama about a special FBI unit staffed by young agents, including 23-year-old Gaia (Rachael Leigh Cook of ''She's All That''), who was born with a genetic defect that prevents her from feeling fear. The show is based on a popular young-adult book series.

''Tarzan and Jane'' will offer a contemporary twist on the legend when Tarzan is brought against his will to New York City and meets Jane, a police detective.

The network's four new comedies include a variety/talk show hosted by Steve Harvey and an autobiographical series about fathers and sons from comic actor Anthony Anderson called ''All About the Andersons,'' in which a single dad tries to raise his son in his parents' house. John Amos portrays Anderson's father.

''Smallville'' will be moved to Wednesday nights at 8 to replace ''Dawson's Creek.'' A ''Gilmore Girls'' spinoff will debut in midseason.

The WB's lineup has gotten Madison Avenue's attention. Daily Variety reported this month that at least one media analyst expects the network to charge ad rates next season that will be 27 percent higher than they are this season.

Pepsi-Cola North America is one believer. The company chose the WB as its partner in a promotion that will include the largest cash giveaway in game-show history. ''Play for a Billion,'' which will air in September, will allow 1,000 randomly selected Pepsi consumers a chance to win $1 million based on a lottery. In what is sure to be a television event, that winner will then have a shot at winning a $1 billion prize as well, also based on a lottery. ''We chose the WB because of its teen audience,'' says Dave DeCecco, a Pepsi spokesman. ''They're the hottest network in that demographic. They are definitely a network on the rise.''