I need to identify the currently running services but I can't figure out the results of running service --status-all, I mean what does ?, - and + mean ?

$ service --status-all

 [ + ]  acpid

 [ + ]  anacron

 [ + ]  apparmor

 [ ? ]  apport

 [ ? ]  atieventsd

 [ + ]  avahi-daemon

 [ ? ]  binfmt-support

 [ + ]  bluetooth

 [ - ]  brltty

 [ + ]  console-font

 [ + ]  console-setup

 [ + ]  cron

 [ + ]  cups

 [ + ]  cups-browsed

 [ - ]  dbus

 [ ? ]  dns-clean

 [ + ]  friendly-recovery

 [ - ]  grub-common

 [ ? ]  irqbalance

 [ - ]  kerneloops

 [ ? ]  killprocs

 [ + ]  kmod

 [ ? ]  lightdm

 [ - ]  lm-sensors

 [ ? ]  mysql

 [ ? ]  networking

 [ ? ]  ondemand

 [ ? ]  pppd-dns

 [ - ]  procps

 [ - ]  pulseaudio

 [ ? ]  rc.local

 [ + ]  resolvconf

 [ + ]  rfkill-restore

 [ + ]  rfkill-store

 [ - ]  rsync

 [ + ]  rsyslog

 [ + ]  saned

 [ ? ]  sendsigs

 [ + ]  setvtrgb

 [ ? ]  speech-dispatcher

 [ - ]  sudo

 [ + ]  timidity

 [ + ]  udev

 [ ? ]  umountfs

 [ ? ]  umountnfs.sh

 [ ? ]  umountroot

 [ - ]  unattended-upgrades

 [ - ]  urandom

 [ + ]  virtualbox

 [ - ]  x11-common

And would running this command with sudo make any difference ? I tried it and in my case it didn't make any difference, but may it differ in other setups ?