They may provide a limited number of pieces to local jewelry stores to showcase their work, or their reputation is spread by word-of-mouth among couples shopping for unique, designer wedding bands and engagement rings.
Between the information provided by consumer reviews, microwave oven ratings, industry analysis and word-of-mouth recommendations, you should be able to easily determine who makes the best microwave ovens.
SAS Wink shoes are comfort loafers for women from the well-known walking shoe collection sold almost exclusively at brick-and-mortar locations and advertised strictly by word-of-mouth.
British company Moonfruit is also a site that offers similar services to the above sites, but has its own social-media story as it launched a viral word-of-mouth campaign in 2009.
Depending on how the giver was notified (via formal announcement, reading about the engagement in the newspaper, word-of-mouth, etc.), no response may be necessary to the news.