If you're trying to engage or inform your community online, it helps to understand who is -- and is not -- likely to be online at all. Four recent Pew Internet reports can help you map out this complex demographic issue.

Who's Not Online and Why explores the current demographics of the U.S. digital divide. Pew found that, as of May 2013, 15% of American adults do not use the internet or e-mail. Groups that were least likely to be online include:

• Seniors: 44%
• People who did not graduate high school: 41%
• People from households earning less than $30,000/year: 24%
• Hispanics 24%
• High school graduates with no further education: 22%
• Rural dwellers: 20%

The most popular reason why people don't use the internet? One-third of respondents cited a lack of relevance: they're not interested, think it's a waste of time, are too busy, or simply don't need or want internet access.

The main ways that people access the internet are via a wired or satellite connection, or via mobile devices. Home broadband is particularly key for gaining full benefits from online access. According to Pew, "While 76% of adults use the internet at home, another 9% say they use the internet but do not use it at home. And though most home internet users have broadband connections of some sort, 3% of all adults still connect to the internet at home via dial-up."

In Home Broadband 2013, Pew found that the same groups least who are least likely to be online at all are also the least likely to have home broadband access:

• People who did not graduate high school: 63% lack home broadband
• Seniors: 57%
• Hispanics: 47%
• People from households earning less than $30,000/year: 46%
• High school graduates with no further education: 43%

Many people access the web or e-mail from their cell phones. In Cell Internet Use 2013, Pew found that "63% of adult cell owners now use their phones to go online. …In addition, 34% of these cell internet users say that they mostly go online using their cell phone. Therefore, 21% of all adult cell owners now do most of their online browsing using their mobile phone -- and not some other device such as a desktop or laptop computer."

Although the other two Pew reports found that Hispanics tend to be especially likely to fall on the wrong side of the U.S. digital divide, they are also especially likely to go online from their cell phones. Nearly 70% of Hispanic adults access the web or e-mail from their phones -- and 60% report that their phone is their primary form of internet access.

Other demographics most likely to go online mainly via their cell phones are:

• Young adults aged 18-29: 50%
• People who did not graduate high school: 45%
• People from households earning less than $30,000/year: 45%
• Non-Hispanic blacks: 43%
• People from households earning $30,000-$49,999/year: 39%

Bridging the digital divide is crucial for engaging and informing your complete community, especially "underserved" demographics. Print, broadcast and phone-in efforts (including newsletters or fliers, newspaper inserts, TV/radio programming and PSAs, 411-style information services, etc.) as well as real-life efforts (events, walk-in services or classes at libraries and community centers, etc.) as well as mobile-friendly online offerings (especially via the mobile web) can be crucial.

Text alerts and interactive text messaging services might also prove helpful. In Cell Phone Activities 2013, Pew found that 81% of all U.S. adults send and receive text messages. Text messaging is even popular with several of the demographics least likely to be online at all:

• Hispanics 87%
• People from households earning less than $30,000/year: 78%
• High school graduates with no further education: 77%
• Rural dwellers: 76%
• People who did not graduate high school: 71%