The digital world can be tricky for teachers.

Those who grew up in the pre-Twitter era are often left casting about to learn how to use new technology and keep up with students.

Others, comfortable with using text messages and Facebook to make connections, find themselves questioning, as they navigate the new frontier, just where students fit in.

Studies by the National School Boards Association show roughly three-quarters of students ages 9 to 17 with Internet access use social-networking tools weekly.

With such rocketing popularity, some teachers have started using the new tools to build rapport, update students on classroom activities and keep an ear to the ground with the youths they teach.

But potential pitfalls remain, including the appearance of impropriety and other ethical issues. And sometimes it leads to criminal cases.

Police last weekend arrested a 36-year-old, eighth-grade teacher at Utterback Magnet Middle School, alleging he had a sexual encounter with a student on school property. The mother of a 15-year-old student had told police she found suspicious chats between the teacher and her daughter on the girl's Facebook page.

And just Friday, a 37-year-old math teacher at a suburban Philadelphia high school was accused of having sex with one of her students and sending sexually explicit Internet and phone messages to another. Police say the teacher used Facebook to contact the students. The sexual relationship reportedly began with one student after she sent him a "friend" request to be part of her online social network.

For students, cyber-interaction is a normal outgrowth of what they do every day.

Zach Khalil, who just graduated from Tucson High Magnet School, said teachers have never "friended" him on social-network sites or texted him, but he wouldn't have a problem with it.

"I can see how it would be an efficient way to get answers to questions about homework," he said, noting the nature of the communication is more important than the mode.

Pablo Chavez, a 17-year-old who just completed his junior year at Howenstine High School, said he has cell phone numbers for two teachers stored in his own cell phone. "I have them in case I don't go to school or if I'm running late or if I miss out on something, I can text them and see what's going on. It's way faster and more convenient."

Chavez said he received some more personal, just-checking-in kinds of text messages from one of the teachers after the two discussed some problems he was having. "It's like standard stuff. She would just text to say, 'Is everything going OK?' - stuff like that."

And for Chavez, that worked. "It shows that they actually do care, instead of just saying it."

Still, he said, he'd likely find it "creepy" to have a teacher show up as a friend on his MySpace account, which he considers a more intimate venue than texting. "I probably wouldn't respond. And if I saw them at school, I'd just ask, 'What's up with that?' "

School officials say it's hard to know where to draw the line - although there has been some movement to do just that.

The Missouri state Legislature is debating a proposal to ban elementary school teachers from having social-networking friend-ships with their students. And the Lamar County School District board in Mississippi recently passed a policy that bans "fraternization via the Internet" between staff members and students. It also prohibits text messages to students except for educational purposes.

Michael Pruitt, vice president of the board, said the district acted on advice from a local lawyer, well-versed in school law, who was concerned with what he saw in his practice. As technology becomes more pervasive, Pruitt said, the board felt it needed a proactive policy.

"We did it with the explanation that we're not just protecting the kids, but we're protecting you as an employee, also."

Because the issue isn't clear-cut, it's often a topic of conversation in ethics classes taught by Sheri Bauman, the director of the school counseling program at the University of Arizona.

Her university students have said they could see educational uses for using networking sites. Teachers might discover interests or hobbies that could help them engage kids in the classroom. They might be able to see whether there's anything going on outside class that's affecting academic performance.

"Many teachers may think: 'If this is how my students communicate, this allows me to relate to them. I can be seen as someone who understands youth and is approachable.' "

She also has known teachers who have "friended" students so they could take on parental roles. Since many junior high students see having a large number of friends as a sign of popularity, they often accept friend requests without screening them - and often are mortified to find out an adult has seen a particularly provocative outfit or comment.

On the other hand, Bauman said, there are risks. "The kind of interaction that often occurs on the site is more personal than the average teacher wants to be with a student," she said. "And with no facial clues or voice clues, that kind of communication is just much easier to misinterpret."

Bauman herself uses Facebook when she needs to contact her graduate students. "I can't say 'Never friend students' if that's what I'm doing myself. It's just a tough call. I think teachers really want to be helpful and go the extra mile to encourage their students to be successful."

Larry Berry, a parent of a fifth-grader at Wrightstown Elementary School and a freshman at University High School, supports developing clear-cut policies, but he said parents play a role. His 14-year-old, he said, has always been trustworthy, but he still monitors the call logs on her BlackBerry periodically.

"From my standpoint, the cell phone, the Twitter accounts - those are the equivalent of pen and paper in a school. Just like everything else, technology and the proliferation of it is good and it's necessary and it's going to happen. So as long as there are guidelines and parents get engaged, I don't see that there would be much of a problem."

Barbara Williams, a Buena High School social studies teacher, said it might sound "stodgy and stuffy," but she doesn't "friend" current students. Students are advised of class information on a school Web page only. And she gives out her personal cell number only to parents.

"It's a generational issue," she said. "Our younger teachers out of college have MySpace and Facebook and LinkedIn accounts, and are not necessarily aware of some of the dangers that are there. It's not that they're unprofessional, but they may not realize the pitfalls."

Having said that, she added that technology needs to be embraced. When the younger cadre came in with ideas for streaming video and podcasting and wikispaces, she said, it got the entire teaching staff enthused.

"We're teaching a different generation of kids, and they learn a different way. This is super stuff - if we use it responsibly."

Rhonda Bodfield reports for the Lee Courier News Service.