TERRY WEBSTER picked me out of a crowd of reporters. She asked me a question that she would have rather asked her daughter.

"Have you gotten taller since last time?

The last time, for we, who during the spring. Terry and husband George had drives here from their New Jersey home to empty their daughter's dorm room.

The last time, for their daughter, Joan L. Webster, was Nov. 28, 1981. Terry and George said good-bye to Joan, who was home for a Thanksgiving visit and she, a second-year student at the Graduate School of Design, took an Eastern Airlines flight back to Boston.

Joan Webster, then 28, disappeared that night. She was spotted at a luggage at Boston's Logan Airport but has not been seen or heard from since.

In the eleven months since her disappearance. I've learned a lot about John--who much as a person could without normally meeting her. I know about her undergraduates background (Syracuse University), What kind of friends she liked (outgoing athletic), how she enjoyed spending most evenings (at the theatre), what kind of records she listened to (James Taylor, Janis Joplin).

I know that the friends of hers I interviewed could easily recall a story to explain home of the ways Joan had touched them. "We lived together during our first year (at the GSD)." one friend said. "During the first week, I was lost, but Joan had already learned everyone's name, where they had group up, all about them."

Shortly after she was reported missing, about 30 of Joan's friends spent several weekends canvassing New England with information about the search. They had hoped, and Joan's parents continue to hope, that publicity may encourage one of the people who knows why Joan disappeared to contact police.

"Some person out there knows what happened to her," father said Tuesday at a Boston news conference. It had been called to announce that a toward for information leading to Joan's whereabouts has been increased from $10,000 to a maximum $50.000. An executive with an international conglomerate. George Webster appeared calm and confident throughout the conference. Terry, a red-haired, conservatively dressed housewife, rarely displayed signs of emotion.

"I've never dealt with any better people," says State Police corporal John O' Rourke, who has been involved with the search since it began, of the Websters.

"There are no hard leads. There never were any. You had facts from day one. A Wallet, a suitcase. There were no fingerprints," he says "Right now, I'll take anything I can get" from individuals responding to the reward offer. "I feel very bad for these people," he adds after a moments pause. "I have children myself."

THAT COMMENT seems to explain, in part, the appeal of the Joan Webster story. There have been front page articles in the Boston Herald American, prominently-displayed stories in the Boston Globe, several stories in the New York Times, and others carried on the national wire services. At this week's conference, about two dozen reporters, from print, radio, and television, bounded the Websters for "personal details" of their emotional trauma.

Educated and firmly entrenched in the middle class, the Websters have learned quickly how to sell their story and thus keep the search alive. Though they have grimaced or bitten their lips after repeatedly being asked, "But, do you think your daughter is dead," they have always answered politely.

And the answer has always been the same, "Until you find her body, there is at least a glimmer of hope."

The Websters have learned that inside anecdotes help to make a news story more saleable. At Tuesday's conference, Terry said that the picture on the new reward poster had once hung in the library of their Glen Ridge, N. J. home. But the large, framed photo has since been removed because "it was too much," George explained.