Last month, I was asked to talk with our new staff about their use of social media. The school district wants teachers to share the awesome things they’re doing. We have a strong online community of teachers, parents, and school supporters, and we want our new folks to be part of that.

There are dangers, certainly. Some students can’t be photographed. We generally don’t identify kids in photos that we do post. We have some established safety guidelines. So we went over that stuff. But the experience gave me the opportunity to reflect on my use of the Internet, and the things I’ve learned about interacting online.

It’s been a while, now. My first experience with the Internet was in October, 1989. I discovered Usenet and email and the oh-so-lovely CoSy. The idea that I could type something here on this terminal, and that it could be seen by other people all over the world within minutes was astounding. I often say that I’m a difficult person to impress with technology. Most “innovations” are not really all that innovative. But this was really cool. I felt connected to other people who shared my interests, even though there was no way we would ever meet face to face.

A few things have changed since then. The mouse. The web. Portable technology. Wireless networking. Phones. But fundamentally, I’m still typing stuff on this keyboard that people all over the world will be able to read in a few minutes. That’s still astounding.

And, in some ways, horrifying. Because once I release my thoughts into the world, I’ve given up control over them. That was the first thing I shared with the new teachers: the cost of sharing is control.

If I have a secret, the only way I can be sure that no one else knows is to not tell anyone. Once I’ve shared it with someone, I can never be completely sure that they haven’t shared it with anyone else. When we’re talking about secrets, we learn who we can trust and who we can’t. We figure out what kinds of things we can tell people, and weigh the risks and the benefits.

But technology companies are not trustworthy. Even if they say they don’t share your data, you have to assume that eventually your secrets will be revealed. Tech companies innovate quickly. They don’t always spend as much time on security as they should. They frequently get acquired or merge or go out of business, and little thought is given to protecting your secrets in these scenarios. And, most of them can change their privacy policies or terms of service whenever they want. You ARE checking regularly to compare their current terms with the ones you agreed to when you signed up, right?

That doesn’t mean we shouldn’t share things online. But we have to assume that everything we put on the Internet will eventually be public. As a college Freshman, I didn’t think that those posts I made on rec.music.beatles would still be there more than 30 years later. But if you know where to look, you can find my 19-year-old words in all their arrogant, self-assured ignorance.

And yet, perhaps the greatest paradox of the Information age is the fact that the Internet is so fragile. Everything lasts forever online. That’s true. But it doesn’t stay in the same place. Last weekend, I was looking for a webcast episode that I did back in 2008. I found the post. But the link to the audio is broken. And the video embed used Flash, which has been gone for a long time now. The chat log was there, but most of the links that we put in the chat don’t work anymore. We used to organize all of those links — in Delicious. Delicious has been gone for a long time, and all those links are gone too.

I learned long ago that I have to make copies of the things I really care about. Consider the pictures on my blog posts. I try to link to the source, but I always make a local copy of the image, because the source may go away. If you scroll back far enough, you can see where I started doing that, because before that, most of the photos are missing. The Internet is ephemeral. Maybe it’s like throwing a plastic water bottle into the ocean. It’ll be in the ocean forever, but good luck finding it.

With the new teachers, we also talked about personal and professional profiles online. Specifically, we cautioned them about online posts that speak on behalf of the school and those that speak on behalf of an individual. They’re different, and they follow different rules. I explained those rules. Then, I told them they’re not that different.

You can have a personal Instagram account and a professional Instagram account. On the personal one, you share photos of your kids and your vacations and holidays at your house. On the professional one, you share photos of cool projects you’re doing in your classroom, and special events happening in your school, and awesome things that your students are doing.

But don’t ever think that there’s no connection between the two. You can’t really be two people online. They will always bleed over into one another. Maybe your uncle is a principal. Or your neighbor is also the PTA president. That quiet kid in the back of the room goes to church with your cousin’s family. We are connected in many ways. The Internet helps us stay connected, and increases the ways in which we can interact. And the lines between personal and professional get blurry.

That’s okay. It needs to be okay. The days when we thought that teachers lived at school and had no life outside the classroom are over. We can have personal and professional lives. We can have personal and professional online spaces. That’s healthy. Just don’t delude yourself into thinking that your students will never see your personal stuff, or that your family will never see your professional posts.

I’ll just stop here and say that, despite indications to the contrary, I did in fact have pants on in that photo.

But you haven’t seen that photo unless you’ve REALLY looked for it. If you Google me, it’s not going to show up in the first couple hundred results. There’s a lot of stuff about me online. Most of it is stuff that I’ve shared. Most of that is relatively positive. Sure, there’s some embarrassing things, and plenty of situations where I’m being an idiot. But most of it is pretty positive. And the good stuff (I hope) outweighs the things I’m not particularly proud of.

You’re going to have digital footprints. At this point, if I Google you and NOTHING comes up, that’s pretty suspicious. That’s especially true if you’re looking for a job working with students who are going to need to navigate an information-abundant society. If you share the good things, you get to control your own identity. It’s your web site or Twitter feed or social media account that comes up in search results, rather than others talking about you. Some of that will be professional. Some of it will be personal. But all of it will be you.

Share the things you’re passionate about. The Internet, for all its faults, is still an amazing resource. But know that it’s not private or temporary, and try to outweigh the embarrassing with the awesome.