Sometimes I’ll see things like my name partially concealed as J*** C*** and think “a lot of good that does.”
Masking letters reveals more than people realize. For example, when you see that someone’s first name is four letters and begins with J, there’s about a 70% chance they’re male and there’s a 44% chance they’re named John. If you know this person is male, there’s a 63% chance they’re name is John.
If you know a man’s name has the form J***, his name isn’t necessarily John, though that’s the most likely possibility. There’s a 8% chance his name is Jack and a 6% chance his name is Joel.
All these numbers depend on the data set you’re looking at, but these are roughly accurate numbers for looking at any representative sample of American names.
Some names stand out more than others. If I tell you someone’s name is E********, there’s a 90% chance the name is Elizabeth.
If I tell you someone’s name is B*****, there’s a 77% chance this person is female, but it’s harder to guess which name is hers. The most likely possibility is Brenda, but there are several other possibilities that are fairly likely: Bonnie, Brooke, Brandy, etc.
We could go through a similar exercise with last names. You can probably guess who S**** is, though C***** is not so clear.
In short, replacing letters with stars doesn’t do much to conceal someone’s name. It usually doesn’t let you infer someone’s name with certainty, but it definitely improves your chances of guessing correctly. If you have a few good guesses as to someone’s name, and some good guesses on a handful of other attributes, together you have a good chance of identifying someone.
An example of this I’ve seen – fill in the names for first and middle initials F (7 letters), X (6 letters). 6 letters starting in X is quite likely to be Xavier, and once you have that the F is very likely to be Francis, after the founder of the Jesuits, Francis Xavier. (Upon checking the data, “Xander” is more common than I realized lately.).
As for J (4) + C (4), literally just before reading this post I saw a post at Hacker News linking to jackcook.com and thought “huh, that’s interesting – probably not related to John Cook”.