80% of Americans earning more than $250,000 pa are social media users

"The reasons for going online are, as most other industries already know, compelling. Eighty percent of people with an income of over $250,000 are social media users according to Unity Marketing research, and 50 percent have used social media to learn more about a brand or see new products. Data from small business consulting firm Lex Consulting shows that those earning more than $150,000 are the only people spending more than they did before the recession. And a 2011 Digitas study notes over the next decade digitally entrenched millennials will become the next major luxury buyers—and should therefore be targeted now."
Source:  AdWeek, 12th September 2011
Note - While they don't explicitly say it, I'm assuming that the research quoted is for the US only

98% of Affluent Americans use the internet

"IAB found that 98 percent of affluent consumers use the Internet, compared with 79 percent of the general population. Wealthy Americans spend around 26 hours online each week, 18 hours watching TV and about eight hours listening to the radio. The general population, on the other hand, spends about twice as much time weekly with TV and radio – 34 hours and 16 hours, respectively – and just about 22 hours on the Internet.
Other key data points show affluent users are just as capable of advertising recall. Eighty-eight percent of affluent consumers recalled being exposed to at least one digital ad during the previous week, compared with 84 percent of non-affluent Internet users. Within these groups, affluents recalled 21.1 ads on average, versus 20.2 for other groups."

Source:  Data from the IAB, reported by Venture Beat, 1st August 2011

Note - "The study defines “affluent Americans” as people with at least $100,000 annual incomes. They comprise 21 percent of U.S. households, have 70 percent of all consumer wealth, and spend 3.2 times more than other Americans on purchases."  (So that's household income, presumably)

Wealthy Americans still look for bargains online

"The nation's most affluent consumers are shopping online more often than other consumers, but that doesn't mean they're heading to sites that appeal to only the wealthy.
According to Unity Marketing's most recent survey of ultra-affluent consumers (those making more than $250,000 in annual income -- the wealthiest 2% of Americans), Amazon.com is the top shopping destination for about 45% of the demographic. That is more than two to three times greater than the next-most-popular Web site, Unity Marketing's President Pam Danziger tells Marketing Daily.
"[Amazon.com] has been a cornerstone of Internet shopping since e-commerce first began and has consistently adapted to the needs of its customers in order to build a loyal following," Danziger says. "For the most discerning affluent shoppers, Amazon offers outstanding levels of customer service along with an expansive product selection."
Yet the nation's wealthiest consumers are also looking for bargains online. Fourteen percent of shoppers went to eBay, 10% used Groupon and 8% hit Craigslist.com. Wealthy shoppers are also heading to flash-sale sites such as Shopittome.com, Gilt.com, Hautelook.com and Amazon's entry into the category, MyHabit.com."
Source:  MediaPost, 7th July 2011

How affluent Europeans use their mobile phones

Click to enlarge

Source:  Press release from Synovate for the 2011 EMS Survey, 14th March 2011

Note on methodology & sample - "EMS 2011 represents the highest-earning 13% of the population in 20 markets across Western and Central Europe. Refinements to the design of this, the 16th release of EMS, include consumption of media brands via mobile applications and mobile websites. This is the first year that an EMEA-wide set of data, combining results from Europe, the Middle East and Africa, has enabled at-a-glance comparisons between markets as diverse as the Czech Republic and Cameroon, mirroring the multi-region planning priorities of many advertisers. From next year, we’ll be including Turkey too."