Skirmishers can shoot in any direction, though individuals models can be pivoted on the spot so that the unit looks more realistic (this does not count as movement).
Thanks to their special training and loose formation, skirmishers do not block the line of sight of other members of their own unit (including characters that have joined the unit).
Note that units of skirmishers block the line of sight to other units (see diagram). It is not possible to see through the gaps between skirmishing models.
An enemy shooting at a skirmishing target suffers a -1 to hit penalty in the same way as if they were shooting at a single man-sized model. See the Shooting section for to hit modifiers.
If a character is fighting as part of a skirmishing unit of troops the -1 to hit penalty is applied only once, not twice.