Sentence case forces only the first word (and I'm assuming proper nouns like people's names) to be capitalized while title case forces all words to be capitalized.
However, is it possible to customize title case to not capitalize every word? I'm asking because, as you guys know, some words are prepositions, which are not capitalized in a title unless they are at the beginning or end.
Just as an example, if I were to make a thread and typed "This is a thread about the dangers of driving," when I submit it, with title case enabled, it would look like so: This Is A Thread About The Dangers Of Driving
However, as there are some prepositions in there, it should be: This Is a Thread about the Dangers of Driving
I think the real issue here is one of personal preference and the desire to follow a set of grammatical rules from before the days of computers which IMO are inappropriate for modern methods of communication. At one time I also worried about "proper capitalization" by old standards, but lately I find I'm not bothered by and even prefer "Title Case" which capitalizes the first letter of every word regardless.
The truth is, most people who post online don't know or don't care about following strict grammar anymore - those who do are in a minority. And it would be quite resource intensive to teach our computers all of the nuances of grammar necessary to follow the old rules. True, for an intelligent person who actually cares it's not hard to follow the classical capitalization rules, but for a computer it's quite involved - it would take a *lot* of code to cover everything that might be entered. I think over time title case will become the accepted form of capitalization for computerized English.
I also disabled Title case and went with a custom set of rules for thread titles. The script I'm using capitalizes the first letter of each word and otherwise retains what is entered, except in the case of shouting (all capitals), where all of the letters are first converted to smalls then then the first letter of each word capitalized.
This won't fix every conceivable problem, but works quite well for the vast majority of titles entered.