[klission]

> It mimics the gmail look & feel, i.e. one line of text represents one thread in your inbox

folder-hook . "exec collapse-all"

set sort=threads

set sort_aux=last-date-received

[telemachos]

Yup. I do this since I'm used to za in Vim for toggling folds:

    # Collapse all threads by default, except if 
    # there's new mail in one.
    unset collapse_unread
    folder-hook . "exec collapse-all"
    # Toggle collapsed threads with za, like in vim.
    bind index za collapse-thread