The global manufacture of intangible heritage

Vevey's Fête des Vignerons has just been inscribed on Unesco's list of the world's intangible heritage. Apart from the Basel Carnival and yodelling, other - more surprising - Swiss traditions were nominated, such as avalanche risk management and Swiss graphic design. What, in short, does the term intangible heritage cover, and what does the growing importance accorded to intangible aspects by Unesco signify?