There is also a page for canned comments.
The "How to ... ?" form for a question is not a good one (does not follow QUASM)
Capitalise "i" - yes, you!!!!!
Small formatting changes often result in a large diff in the default view.
Meta information does not belong in a question or an answer. See for example Should 'Hi', 'thanks', taglines, and salutations be removed from posts?
Statements like "the above" may make sense on a forum, but definitely not on Stack Exchange.
"its" vs. "it's"
Links shouldn't be naked - use an appropriate link text.
Many users post sloppy or even misleading indentation of code.
Shorthands or TLAs often make posts too obscure for the actual audience (from search engine hits).
Inappropriate shortening of "IP address" (IP addresses are blocked, not the protocol).
Capitalisation often obscures the meaning when proper nouns are involved.
Code formatting should not be used for emphasis.
Unfortunately, Stack Exchange does not warn when text is enclosed in "<>". It is just ignored and becomes invisible without warning.
Things like "Update", etc. do not belong in the main post (question or answer). A post's current version should be the best possible and there isn't any need to know how it changed over time - this information should be in edit summaries and in the revision history (in some cases, and/or in comments), but definitely not in the main post. Remember, 99% of the users for a post comes from a Google search, and they have no interest whatsoever how a post changed over time - they just need the best content (besides, it is ugly to have "Update" in a post).
It is not necessary to capitalise any words for emphasis. Both Stack Exchange, Wikipedia, Quora, and even YouTube (though very poorly documented - see my blog post about how to reliably style YouTube comments) have facilities for bold and italics. It is mostly Indians who do this, but not at all exclusively. Anyone who has wasted too much time with (raw text-only) forums will have the tendency (and need to unlearn).
Spelling of Stack Overflow, Stack Exchange, and other Stack Exchange sites, etc. No matter how it looks in a logo, it is "Stack Overflow" and "Stack Exchange" (the last section - "Proper Use of the Stack Exchange Name"). See also Naming guidelines on the "Stacks" design system. The only exception is "MathOverflow" (and Jeff Atwood should have said no at the time).
Rhetorical questions do not belong in an answer. One of the reasons is that an answer should not address the OP - most readers (e.g., 99.9999%) will be someone else.
Most older posts on Stack Overflow have strange syntax highlighting, probably caused by later changes to the Stack Exchange software. Possible code fencing formatting (note: broken in late 2024): ```lang-none, ```lang-html, ```lang-php, ```lang-javascript, ```lang-css, ```lang-java, ```lang-csharp, ```lang-vbnet, ```lang-python, ```lang-xml, ```lang-bash, ```lang-typescript, ```lang-yaml, (Dockerfile) ```lang-kotlin (.kts)
Run-on sentences (YouTube video). Mostly native speakers (more pronounced for US native speakers), but also for minimum-effort users:
Missing articles, Russians and Indians, "a":
Missing articles, Russians and Indians, "the":
The Indian space (from the outdated 1935 Wren & Martin textbook)—keyboard shortcut hint: c:
US native speakers, especially southern US, "than" vs. "then":
US native speakers, especially southern US, "you're" vs. "your":
US native speakers, especially southern US, "there" vs. "their" vs. "they're":
US native speakers, especially southern US, "affect" vs. "effect":
US native speakers, especially southern US, "where" vs. "were"vs. "we're":
Space between quantity and unit:
Present simple tense, third person singular - there must be an 's':
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