Writing about web page http://www.dreaded-apostrophe.com/
There is a take-away food shop near my house called Wongs.
If it was written with an apostrophe, as in Wong's then the name of the shop would mean "the place belonging to a person called Wong". But as it stands, written Wongs, it means instead "many people called Wong". I'm almost tempted to commit my first ever act of graffiti and go and spray an apostrophe late one night.
A fascinating insight to the origins and usage of the apostrophe in modern English is available at the excellent website The Dreaded Apostrophe. It starts with the improbable-sounding claim that there is one rule, only one rule and nothing but one rule to using the apostrophe:
Use an apostrophe when letters are missing.
Pretty obvious for contractions such as don't but less obvious for possessives such as Wong's Shop.
The website explains that the rule holds for possessives because in old English you used to add an 'es' to nouns. So in old English we would write the bookes title ; the bookses titles ; the womenes hats and so on. In modern English the apostrophe replaces the 'es' in words ending 'ses' and replaces the 'e' is words ending 'es' (without a preceding 's'.) So we have the book's title ; the books' titles ; the women's hats and so on.
Sometimes it's optional. Joneses blog in old English becomes either Jones's blog or Jones' blog and both are correct.
That said it can still be confusing. For example, consider how to rearrange the following to use a possessive form instead of 'of'...
The hats of the mothers-in-law.
The hat of the mothers-in-law. (i.e. many mothers-in-law have shared ownership of one hat – improbable I know!)
The hats of Bill and Ben.
The hat of Bill and Ben. (Bill and Ben have shared ownership of one hat.)
The budget of the union of the students.