I'm often uncertain about how I should capitalise headlines for professional writing on the Web.
The two options I'm talking about are:
Just capitalise the first word and any other words that would need capitalising in a normal sentence (sentence case).
Capitalise Every Word in the Sentence Apart from Articles, Prepositions and Other Bits and Pieces. (Title Case / Headline Case).
My concerns are:
Sentence case seems easier on the eye to me, and is less aggressive.
Sentence case may seem too casual though, even for the Web, and appear unprofessional.
Title case can seem 'spammy' and may be associated with low-quality content.
I'm aware that the Web offers a lot of variety in formality and what is appropriate, so my question focuses specifically on 'Web only' writing that doesn't easily fit into traditional categories such as magazine, newspaper or encyclopaedia content.
TL;DR Should I use title case or sentence case for professional writing on the Web?