TO some, the idea of collecting tiny paper squares - stamps - seems pointless, or at best uninteresting. They imagine that stamp collecting cannot compare with, say, skiing or roller-skating in terms of excitement, nor can it rival antique-collecting for snob appeal. One would think philately was a doomed hobby, fit only for a senior citizen's pastime. But prepare yourself for a surprise. Those gummy squares of paper have a tremendous status in Hong Kong. No other country in the world sells out every new stamp issue in a single afternoon. Die-hard philatelists (stamp-collectors) had cause to celebrate during the four-day Hong Kong '94 Stamp Exhibition at the Hong Kong Convention and Exhibition Centre, which ended on Monday. Organised by the Hong Kong Philatelic Society and the Hong Kong Post Office, the exhibition was touted as the largest regional stamp exhibition ever held in Hong Kong. Crowds filled up every niche of the 837 square metre Upper Exhibition Hall, which was converted into a bustling stamp market of buyers and sellers. Fifty-two countries, including Hong Kong, had put up a total of 140 sales booths. The rows upon rows of beautiful stamps attracted buyers from here and overseas. There was a specially commissioned Youth Corner, set up by the China Philatelic Association. Mrs Ellen Siu, management controller at the Hong Kong Post Office, said: ''One of the main aims of the exhibition is to promote philately among youngsters. The first series of hologram (three-dimensional) postcards was also introduced because of their popularity among the young.'' The two hologram postcards, depicting 1920 and 1993 views of the Hong Kong waterfront, carry the faces of Queen Victoria and Queen Elizabeth, respectively. A full programme was lined up for schools invited to take part in the Youth Corner. It included two video clips, one showing how stamps are designed and printed, the other covering the basics of stamp-collecting. A free philately gift-set comprising a stamp album, a micro-lens, pincers and a measuring gauge was handed out to participating schools. Liem Yan-wang, a Form Six student of Heep Woh College, was one of the enthusiastic guests. A collector for five years, he said he liked Hong Kong and China stamps as they were ''easily available and beautifully designed''. Wong Ngai-leung, 18, also from Heep Woh College, started collecting stamps as a child but began taking it seriously only three years ago. ''Every stamp has its own character and design, and all in a small space,'' Ngai-leung said. When asked by a visitor if he thought stamp-collecting was only a ''filler for boredom'', Postmaster-General ichael Pagliari said: ''Every country's history is written on its stamps. Philately is one of the most educational and affordable hobbies around.''