Users of social networking sites are becoming impervious to traditional ads and turning instead to their friends and colleagues for information and product recommendations, according to a new study.

Market research firm Compete Inc. says peers hold more influence over social networkers’ purchases than any other source of information, while over one-third of ‘online socialites’ spend less time watching TV or reading newspapers or magazines as a result of their usage.

Its study found that people join a social networking site for four reasons; to meet people (78%); find entertainment (47%); learn something new (38%); and influence others (23%).

Their annual discretionary income is also 20% higher than other consumers, and they spend nearly 25% of their disposable income on online purchases (versus 17% for others).

Marketers, meanwhile, are using six strategies to target those consumers, says the company – branded micro-sites; customer reviews and ratings; online customer forums; P2P transactions; product-focused blogs; and community-created products.

Committing to a social commerce strategy means welcoming consumer participation throughout the marketing process,” says Stephen DiMarco, its vice president of marketing.