- It is a tactic of limited utility.
Library Data Referral Tree
- Starship Drives
- Jump Drive Key Resources
- Jump Drive Lore
Any jump of less than one parsec is considered to be a microjump. Sometimes, it can be advantageous to jump within a system rather than use manoeuvre drives. If normal acceleration and deceleration would take more than a week, a microjump is more efficient. At 1G, any distance greater than one billion kilometres would be more efficient using a microjump. Microjumps can also confuse an observer or enemy. Because a ship’s jump destination cannot be predicted, a microjump within a system still leaves an impression that the ship has left; a week later, it emerges from jump in the same system, to the observer’s confusion. 
However, regardless of the distance travelled, a jump still takes a determinate (fixed) quantity of time roughly equal to 168 hours (+/- 10%).
- Starships remain in jump space for roughly a week no matter the distance traversed by the jump.
- Starships can coordinate jump travel with exact timing.
- While jumps can be coordinated, ships cannot travel together.
- All starships in J-space appear alone and isolated. 
Extremely talented astrogators can make a reasonably accurate guess as to the destination of a jumping ship if it is observed before jumping. This is based on observation of neutrino emissions and the shape of the inflating hydrogen bubble as well as the heading at the time of jump. What is true is that starships maintain the same general heading, attitude, and velocity at the time of egress from jumpspace as it had upon entry. 
Galactic Drift & Zero Jumps
A point to remember though, in a week the solar system may have moved a bit. These motions are entirely predictable (...outside of star-shattering events such as the Final War), so any in-system jump will calculate for arrival based on how the solar system will be laid out in a week.
"Zero Jumps", which arrive in the same place relative to a planet or other sub-stellar celestial body as the jumping ship departed from, are actually jumps that parallel the body's arc of travel during that week, with adjustments and allowances to breakout some time early or late. Some astrogators have likened this to entering jumpspace, exiting the body's path, looping back into the path (...in front or behind the body), then heading toward the body until catching the edge of the 100 diameter limit and precipitating out. That it takes this much effort to "stay put" is sometimes given as evidence that there is no such thing as "remaining stationary" or "standing still" in space.
Since a jump is 168 hours + Flux a zero distance jump may allow you to accelerate the entire time in a selected direction. With a 1g acceleration a max speed in excess 5931061.92 m/s can be achieved from a 0m/s start (2% of the speed of light!). Of course without using the efficient manoeuvre drives this is an unlikely outcome.
What happens if you jump less than 1 parsec?
- Many people have asked if it is possible to jump within a system, or to just outside the system.
Basically, it is possible and it works exactly like a one-parsec jump. It takes a week with the normal uncertainty factor. The amount of fuel used is also the same as for 1 parsec - (1 divided by the maximum jump range) times the total amount of jump fuel for a full length jump. e.g. A one parsec jump in a Jump-3 capable ship will be 1/3 of the ship fuel required for a 3 parsec jump.
Polystellar Star System Microjumps
In large star systems, or in early stellar cultures where the maneuver drive is less efficient than in later stellar cultures, using the jump drive for an in-system jump may be more time and cost effective than using the maneuver drive to travel to distant locations within the system.  In many Polystellar Star Systems, it may be far quicker to spend a week in jumpspace than travel in normal space, even with a multi-G maneuver drive. 
Zero Jumps & Hiding Out in Jumpspace
A Zero Jump or zero distance jump can also be made. Such a jump allows the jumping ship to remain (...more or less) stationary for a week in jump space. There are times when this tactic can be useful to evade hostiles.  It can be particularly useful when evading opportunistic corsair vessels. You'd still need to be outside 100 diameters, and without proper astrogational calculation, the chance of misjump can be very high. 
As a battle tactic, it is of limited strategic value to large naval fleets, as unfueled ships lose strategic value at their new destination requiring more fueling time during which they will be vulnerable to escorts and fast cruisers. This tactic can fool inexperienced enemies, but is far too old a gambit to fool any but the most inexperienced of fleet commanders or regular naval fleet captains.