There are no daft questions here on the Forums - but there may be daft answers . . .
Don't get too hung up on Contexts. They're one of the building blocks of the GTD approach and, if I may quote from David's revised book, a Context is a physical or psychological environment within which reminders and information are most effectively sorted for access.
The examples given are when one is at home, in a staff meeting, at the computer, feeling creative, near a phone, having a converation with a partner, etc.
When the book was orginal written, computers tended to be on desks, so the physical environment was the deciding factor as to which list an action went on. Now computers (in the form of smart phones and tablets) are so portable and we're rarely without one, that the deciding factor might be more pyschological or take a different physical form.
For instance, I do my Weekly Review out of the house away from distractions, and, when I worked for a living, I would go to the works canteen to do my review. So I have an @cafe Context where I put my Weekly Review actions and also where I put articles that I'd like to read away from distractions. So you could have an @away_from_distractions Context.
In the past, splitting an @computer Context by application - Word, Excel etc. - was often advised, but that was more approriate when firing up each application (and maybe the computer itself) was such a time consuming activity.
Design contexts that work for you and change them if they don't.
If you end up with 95% of your actions on one context, you'll not want to tackle them. Splitting them into smaller groups (contexts) will help.
How do you eat an elephant? One bite at a time!
Dave