Like I said in my post on not being obsessed with privacy, it's rarely worth it to try and stay anonymous online. But sometimes it's necessary. So, here's some advice for different situations.
Preventing mild embarrassment
So maybe you want to write a bunch of trashy fanfiction, or you want to hang out in a really weird forum. Or perhaps you want say something really rude about your mother-in-law. Naturally, you don't want people to find out.
The important thing to remember about this sort of thing is that only a few people who know you will actually care, and they won't be looking for it. So, it's mostly a matter of:
- Separate email addresses, account names, etc., etc.
- Mentioning as few personal details as possible. Especially names and specific locations.
- Not linking or referring to things online that can be linked back to you.
- If you simply want to make a really horrible one-off comment, please reconsider it. If you still absolutely must, create a new alias just for that one thing.
- Stay off the social networks. And I mean completely off the social networks (twitter is okay in isolation). They're set up to automatically tell people all kinds of crap.
Remember, both Google and annoying people work by putting little pieces together to make a big picture. If you don't make connected pieces, they won't be able to either. Also, don't worry about it too much, and remember that nobody really cares about your weird fetish/interest/collection of distorted kitten paintings.
Avoiding bullies and other creepy people
This is harder. You want to be active online, but don't want to deal with people who threaten to punch/kill/whatever you. And, since you deal with sensitive topics, (or in many cases, deal with ordinary topics and happen to be a woman or minority), this happens all the time.
Now, if you're already well known, it's probably too late. (Also, you're probably not reading this!) If you want to keep working with the same people, you'll be found out, even if only by your writing style. But if you're just starting out, follow all of the above, plus:
- Don't trust people you haven't met in person, and for reasons unrelated to your online activities, with anything. Some of them may be trying to gain your trust for unsavory reasons. Look up some of the nastier activities of /b/, encyclopedia dramatic, etc. for examples.
- Don't form strong personal relationships of any sort with people using your 'sensitive topic' alias. Have your say and be done with it. People become disgruntled, or gossip, or accidentally let things slip, and other people can start piecing things together.
- If possible, make this your only major public on-line activity. This prevents people from noticing similar writing styles, reference pools, and so on.
- If you're not a tech whiz, use a major blogging/publishing service, not a shared server, if at all possible, to help stop casual hackers.
- Don't talk to journalists. If you really must, don't say anything you wouldn't publish on your usual outlet.
- Don't worry about Google too much; they're not really set up to track things like this.
So, you're a political dissident. Or you're doing something questionably legal. Or, annoying somebody who's willing and able to hack serious servers and set up wiretaps. People are actively looking for you. Here's what you need to know:
- All the advice above is mostly useless. If your ISP is potentially compromised, things just became an order of magnitude harder.
- Be very, very afraid of Google, et. al. They like cooperating with the government much more than they let on.
- Encryption. Learn about it. Use it. Look up "plausible deniability."
- Think about Tor and other similar schemes, but be aware that most of them have flaws.
- If you're really, really serious, don't do anything directly. Send (possibly using encrypted email, see below) information to a collaborator in a safer jurisdiction, after the manner of old-style secret journalistic sources, etc. Let them deal with the public.
And good luck.
A word about email
Email, curiously enough, was never designed to be secure. In fact, it's arguably the most insecure form of communication we use. Every email you send potentially travels through any number of other computers, each of which can read every single word. Fortunately, there's a solution: GPG. I was going to explain it here, but if you're going to use it, you need to really understand how it works. Read the page. Read it again.
Suffice it to say that when properly used, GPG can both encrypt all sort of communication, and just as importantly, can further guarantee who sent it.
In the absence of GPG or another comparable solution, just assume that your email is being read.