Smart quotation marks are also called curly quotation marks (see above image) as opposed to unidirectional quotation marks ( ” “).
All published works should use directional or “Smart” quotation marks.
Published works should also use smart apostrophes. These apostrophes use the right single quotation mark, not the left.
Published works should use directional (or “smart”) quotation marks, sometimes called typographer’s or “curly” quotation marks. These marks, which are available in any modern word processor, generally match the surrounding typeface. For a variety of reasons, including the limitations of typewriter-based keyboards and of certain software programs, these marks are often rendered incorrectly. Care must be taken that the proper mark—left or right, as the case may be—has been used in each instance. All software includes a “default” quotation mark (“); in published prose this unidirectional mark, though far more portable than typographer’s marks, signals a lack of typographical sophistication. Proper directional characters should also be used for single quotation marks (‘’). The hexadecimal code points for Unicode are as follows: left double quotation mark (“), U+201C; right double quotation mark (”), U+201D; left single quotation mark (‘), U+2018; right single quotation mark or apostrophe (’), U+2019.
Published works should use directional (or “smart”) apostrophes. In most typefaces, this mark will appear as a raised (but not inverted) comma. The apostrophe is the same character as the right single quotation mark (defined for Unicode as U+2019; see 6.115). Owing to the limitations of conventional keyboards and many software programs, the apostrophe continues to be one of the most abused marks in punctuation. There are two common pitfalls: using the “default” unidirectional mark (‘), on the one hand, and using the left single quotation mark, on the other. The latter usage in particular should always be construed as an error. Some software programs automatically turn a typed apostrophe at the beginning of a word into a left single quotation mark; authors and editors need to be vigilant in overriding such automation to produce the correct mark, and typesetters need to take care not to introduce errors of their own. (If necessary, consult your software’s help documentation or special characters menu.)