To reach people in their 20s and early 30s, the most important thing nonprofits can do is to make sure their Web sites are easy to read on a mobile device and not overly cluttered, says a survey of more than 6,500 young people released Tuesday.

About 65 percent of respondents said they liked to learn about a nonprofit through its Web site, compared with 55 percent who said they turned to social networks, e-mail newsletters (47 percent), print (18 percent), and face-to-face conversations (17 percent).

Other findings from the survey, conducted by two consulting companies, Achieve and Johnson, Grossnickle, and Associates:

Keep e-mail newsletters short and to the point. Members of focus groups conducted with the survey said they were more likely to read short, focused e-mails than long messages. About 65 percent of young people said they wanted e-mails to give them news about the organization, and 61 percent wanted information about events.

Facebook is the most popular social network. Two-thirds of young people said they interacted with a nonprofit on Facebook, and 92 percent of those respondents “liked” at least one nonprofit’s Facebook page. Three-fourths of people said they would be willing to share an interesting nonprofit event on Facebook.

Twitter is more personal. About 28 percent of young people said they have interacted with a nonprofit on Twitter. Focus-group members said Twitter is especially useful when nonprofit leaders have their own personal accounts and share their views.

Read the full reports about the survey of the giving and online habits of young people.