By accident, I clicked Edit on someone else's post. I saw my error immediately, because I wanted to edit MY post, not someone else's. Then I wondered, why in the world is this site allowing people to edit each other's posts?
This is answered in the Help pages:
Why can people edit my posts? How does editing work?
All contributions are licensed under Creative Commons, and this site is collaboratively edited, like Wikipedia. If you see something that needs improvement, click edit!
Editing is important for keeping questions and answers clear, relevant, and up-to-date. If you are not comfortable with the idea of your contributions being collaboratively edited by other trusted users, this may not be the site for you.
You simply found that you were one of the "people" editing a post they themselves hadn't written.
While it's true that anyone can edit posts, it's a bit more complicated than just that.
- Everyone under 2,000 reputation can only make suggested edits to other's posts. This means that the edit needs to be approved by one or two 2k+ rep users before it is applied to the post. This prevents many bad edits and trolling.
- Everyone over 2k rep can edit posts freely.
However, any edit that gets applied to the post bumps the post onto the home page. This means edits by even 2k+ rep users are being watched by the community. In addition, nontrivial edits also notify the post owner.
Some specific guidance on when to edit can be found here:
Some common reasons to edit are:
- to fix grammatical or spelling mistakes
- to clarify the meaning of a post without changing it
- to correct minor mistakes or add addendums / updates as the post ages to add related resources or hyperlinks
Tiny, trivial edits are discouraged - try to make the post significantly better when you edit, correcting all problems that you observe.
In addition, there are some special cases where editing works a little differently. English Language and Usage Meta, which is where your post was migrated to, does not allow suggested edits, so users need 2k+ rep to edit others posts here. For more info see:
The reason Stack Exchange encourages constructive editing of posts is that it aims to be a reference site.
Questions must be well-formed, within the charter of the relevant community. Answers must be coherent, should be objectively correct, and must stand on their own even if material on linked sites change or become inaccessible.
There are times that the author of a post formats the post poorly because they don’t understand the text editor’s formatting conventions; or the author disappears without cleaning up their typos. That post would then look untidy to future visitors.
To help improve the quality of posts (and hence the reference site as a whole), the community is encouraged to make edits to improve clarity and correct typos etc. The only proviso is that the intent of the post should be preserved.
I think it arises from the peculiar view that every question has just one right answer, at least for the areas of knowledge that are allowed pride of place on Stackexchange. Opinion doesn't matter -- only knowledge counts. (But of course that's just my theory.) So if a question or answer is correctly amended, this cannot be a misrepresentation. The Truth cannot be questioned.