Erin Bouma's Recommended
For anyone writing in English, you must understand the unique punctuation system.
Wikipedia’s main punctuation page, including punctuation symbols and typography, a brief overview and history.
An illustrative sentence demonstrating the need for proper punctuation to meaning.
Lists other useful punctuation sites. This one is specifically devoted to American English.
Provides a forum for an on-going discussion of punctuation in FAQ, also a mailing list you can join.
Interesting assortment of analogies that have been used to describe the role of punctuation in the language:
romantic “A comma is a delicate kink in time, a pause within a sentence, a chance to catch your breath. A curvaceous acrobat, it capers over the page.” Or
info highway “Punctuation marks are the traffic signals of writing. Without punctuation, many a written passage would become as chaotic as a large city without traffic lights.”
Purdue University Online Writing Lab (OWL). This site has clear explanations of English punctuation patterns and rules with sample sentences. Sentence Punctuation Patterns, Clauses, the Comma, Apostrophe, Hyphen and Quotation Marks.
Sussex University offers this textbook for those who find punctuation difficult and struggle with commas, colons, semicolons, hyphens and apostrophes. It is based on Standard British English, but also includes clearly marked American variants. Two other helpful areas are: 1) a Misc. section for Italics, Boldface, Small Capitals, Parentheses, Square Brackets, The Ellipsis, The Slash, Numerals, Fractions and Dates, Diacritics, The Other Marks on Your Keyboard, as well as Priority Among Punctuation Marks and 2) A Guide to Punctuating Essays and Formal Letters.
WikiHow has a simplified manual of proper punctuation with good examples. Especially useful is the TIPS section at the bottom.
Some good, clear explanations and example sentences. Out of the many important elements of writing, punctuation may be the most essential. It helps direct us through written language with its system of symbols and the rules for using them. Correct usage of punctuation symbols and conventions help the reader avoid confusion and understand more clearly what the writer has intended. Punctuation also affects the rhythm of how a sentence is read, as well as the actual meaning of the writing.
Focus on punctuation and spacing. 20 exercises to do.
Basic rules and examples given. Best at pointing out contrasts.
Two radically different headlines: ‘Police catch man-eating crocodile’ ‘Police catch man eating crocodile’. // I’m an English teacher. I’m an English English-teacher. I’m an English-English teacher.// Compare a changing room with a changing-room. //
AmE: Dr. Cohen is from the U. S. Since 1999 he has been working for UNICEF at U. N. headquarters in New York. He weighs 165 lb (lb.) / lbs (lbs.) and walks 2 miles to work every day.
BrE: Mr Jackson was born in the UK in 1947 but later became a US citizen. Nowadays he’s working for UNESCO at UN headquarters in New York. He weighs 75 kg and walks 3 km to work every day.
The Punctuation Underdog Page offers a New Paradigm and views on writing complications.
“The Philosophy of Punctuation” – article by writer and thinker, Paul Robinson (2002).