Americans like to talk about shiraz, but they don't buy it. Conversely, they buy a lot of malbec but don't discuss it.

Market analysts Nielsen measured mentions of different wine varieties on social media for more than two years, and the "buzz volume" statistics were revealed at the Wine Market Council's annual presentation.

Researchers reported that while moscato is only the sixth most popular variety in the U.S. in terms of sales, it was the second most-talked-about varietal after chardonnay. It's not surprising that moscato is a hot topic on social media: young female drinkers have embraced the sparkling wine, and they are particularly active on sites such as Facebook and Twitter.

What is surprising is that the interest in some varieties isn't matched by sales. Shiraz enjoys nearly twice as much buzz as malbec, even though shiraz sales continue to decline, with a 17.9 percent fall in the U.S. last year. Similarly, riesling gets more buzz than pinot grigio, even though riesling sales have dropped by 4 percent.

"Not all buzz is positive," cautioned John Gillespie, CEO of Wine Opinions. "Within the moscato column, there is a certain amount of 'I wouldn't give up my riesling for moscato if you paid me.'"

The council's statistics continue to show a recovering U.S. wine market, with sales up 2.9 percent overall. Growth was strongest (+14.2 percent) in the $9–$11.99 price category, according to Nielsen. Wines over $12 are doing well, but growth is flat or actually dropping for wines under $9.

The average price of a 750-ml bottle of wine in the chain stores measured by Nielsen was $6.30 in 2012 – an increase of 17 cents.

Domestic sales growth was stronger than for imported wines. By state, Oregon had robust growth of 5.5 percent by volume despite a high average price of $15.12 per bottle, compared to $6.82 for imports and $5.94 for California wines.

Among imports, Argentina and New Zealand had successful years, growing 9.5 percent and 23.5 percent by volume respectively. Americans now drink twice as much Argentine wine as French wine.

Looking forward, red blends are a category to be watched, with sales up by 23.3 percent. Red blends now outsell all red single-variety wines except cabernet sauvignon and merlot.

Wine producers around the world watch these statistics carefully. As Gillespie pointed out, with 100 million regular wine drinkers, the U.S. is the world's No. 1 wine market (even though one-third of American adults don't drink at all). Core drinkers – those who drink wine at least once a week – make up just a quarter of the population, but consume 93 percent of the wine sold.

Gillespie also released preliminary results from a survey of luxury wine buyers – those who drink at least one bottle of wine priced at $30 or more wine per month.

These consumers bought significantly more imported wines, which represented 58 percent of their wine purchases, compared with 26 percent for the population as a whole.

Luxury wine buyers were also willing to spend much more money at retail stores or on direct purchases from wineries rather than in the on-premise sector. "Their purse strings tighten in restaurants," Gillespie said.

He added that in 2012, sales dropped for wines priced at more than $40, although 19 percent of luxury consumers reported buying wines over $100 retail "several times a year." For wines in restaurants, sales dropped off quickly when prices breached $74.

Luxury wine buyers were asked to describe how they use wines by price segment. A majority called "everyday" wines those priced between $10 and $19. A tip to marketers: they said "estate bottled" wines were those priced over $100, which they also called "cellar worthy."

These consumers described wines priced at $30–$39 as a "good gift."

"I guess we know what they think about their friends," Gillespie said.