This is my online commonplace book. According to Wikipedia, a commonplace book is “a way to compile knowledge, usually by writing information into books.” It is often used as a central repository of ideas, quotes, poems, proverbs, observations that a writer or reader or student comes across in reading and studying. A commonplace book is then a way to record and organize these ideas for later use in writing, speaking or other pursuits in life.
The idea and practice of commonplace book had been around for centuries. The practice became popular in Early Modern Europe (from late 15th century to late 18th century). Some famous users of commonplace books: John Locke, Ralph Waldo Emerson and Henry David Thoreau. A famous modern user would be Bill Gates.
In my case, the commonplace book is mathematical in nature. I am already a writer for many math blogs. But those blogs focus on specific areas or topics. This blog, as a commonplace book, will be a place for me to write down interesting mathematical ideas, possibly for further development at a later point.