Ever since the late 1940s, when it occurred to a clever copywriter working for De Beers that "A Diamond Is Forever," young men in love have been walking into jewelry stores to buy diamond rings that will change their lives.

One such destination is Samuel Gordon Jewelers, established in 1904 in Oklahoma City, where the marriage-minded have a very good chance of meeting 39-year-old company president Dan Gordon. If they have never laid eyes on Gordon, there is a very good chance that they "know" this fourth-generation jeweler through Twitter or Facebook, venues that are to young jewelers what country clubs, golf courses, and the Rotary Club were to jewelers of past generations: places to see and be seen.

“Having a Facebook page, having a Twitter account: We’re all turning into our own media machines,” says Gordon, a tech enthusiast who first engaged customers with a Today show-like wedding contest on the company’s website back in 2004. “For jewelers, there’s so much to pull people in, to engage them.”

The most popular time for consumers to “engage” literally, is the holiday season between Thanksgiving and New Year’s, which also accounts for a good third of the store’s jewelry sales, Gordon says. But the urge to get engaged strikes on Valentine’s Day too, and that is a very good thing for jewelers. Couples get married in good times and bad, and bridal sales have been the sole recession-proof category in an economic downturn that has pummeled jewelers.

The bridal category includes wedding bands and maybe wedding-day jewelry for the bride, but the big-ticket item is the engagement ring. So how much do consumers pay for the ring that will be repeatedly held up at eye-level to show family, friends, and envious acquaintances? Gordon says today's bridal customers very rarely mention the “two-month salary rule,” that used to dictate the bill for a diamond engagement ring.

“I think it is kind of passé,” Gordon says, adding that diamond engagement rings tend to sell anywhere in the $5,500 to the $15,000 range. “Some people will bring it up in that they’ll ask ‘How much am I supposed to spend?’ But what I see now is people are buying what they can afford. Sometimes it’s more than two month's salary and sometimes not. It depends on how focused they are on obtaining precisely what the woman wants.”

One way that consumers are encouraged to go for it at Samuel Gordon Jewelers? Social media: Gordon was on Facebook the minute it was accessible to non-college users, and he has been using Twitter for three years. The store has its own blog, a mobile app, and even a Groupon-like discount program called Jewelry Friendzy that hinges on referrals.

Launched before the Black Friday shopping weekend last year, Jewelry Friendzy drew media attention via an appearance on MSN's Business on Main program, but it also helped Samuel Gordon Jewelers deal with a problem that has plagued jewelers nationwide during the recession: excess inventory. For the Oklahoma jeweler, the amount of jewelry sparkling idly in showcases totaled $1 million.

Friendzy let the store have some fun and avoided a "fire sale" promotion, which would have been a little unseemly for a jeweler of Samuel Gordon's caliber, Gordon said. Friends showed friends their new jewelry, those friends popped in to receive their discounts, and the merchandise moved.