It's important to have an audience in mind when writing. What is the writing for? What problems should it solve? Which issues should be addressed, and which ignored? Which tangents should be followed? Which details included, which points elaborated on, which words defined?
Writing needs a problem situation, a context, some selective choices about what it is and isn't trying to do.
Having in mind a target audience gives you a way to make decisions. You shouldn't try to write in a one-size-fits-all contextless way. It's important to make choices and do opinionated writing. Try to accomplish some things really well, rather than having a little something for everyone.
When you're thinking about writing something two different ways, you can think to yourself, "Which way would be better for my audience?" If you didn't have an audience, you could get stuck because each way would be better for some readers and worse for others.
People sometimes write for an audience without being aware of it, because an audience is necessary. Even if it's inconsistent and there's contradictions, each part was for some audience. One can't write completely out of context. But the audience can be vague, ill-considered, change every paragraph, and have other problems.
A common vague audience people write for are what they think "most" people would prefer to read. And they usually mean most people in their social circle, or their country, or who speak the language they are writing in and have internet access, or something.
It's hard to make good choices about writing without some more specific ideas about how to approach it. Choices about what to include or not, and how to present each topic, depend on the audience, context or problem situation you're writing for. Making those choices in a clearly thought out and consistent way makes for better writing.
Sticking your neck out and writing to do some things really well, instead of bland something-for-everyone writing, frequently works better even for people who aren't in the target audience. They'd rather read something thematic over something directionless.
I wrote and edited the Life Articles by thinking about a particular philosopher. If I didn't think she'd mind something, then I didn't change it in editing. For example, she's not picky about capitalization or formal writing. And I included topics I thought would interest her. They're opinionated articles, with a specific style, and I think that makes them better.
I did try to keep things readable for other people. It's impersonal philosophy. And when I thought other people wouldn't know what something was, but she wouldn't need an explanation, then I put in a link to allow anyone to understand.