The RAW...
Let's say there is an area of shadowy illumination. There are two rogues, Rogue A and Rogue B, neither of which has the HIPS ability. Rogue A is hidden 5' from Target. Rogue B is hidden 10' from Target. Rogue A can melee attack Target and remain hidden if she makes a Hide check at a -20 penalty that beats the Target's Spot check. Rogue B has two options. She can snipe, then hide at a -20 penalty per the Sniping rule. Or she can can make a ranged attack at a -20 penalty to remain hidden while attacking. The standard attacking rule (-20 penalty to hide while attacking), is superior to the sniping rule (which makes you visible before hiding again), since if you become visible before hiding again, you become vulnerable to readied attacks.
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Not the RAW...
IMO, the thing that stands out about the sniping rule is that it is sort of a HIPS ability. The sniping rule says Rogue B is not hiding while attacking, but hiding after attacking. Since Rogue B is not hiding while attacking, she is visible to Target. But after Rogue B's attack, she can hide again, at a -20 penalty, even though she is visible to Target. In other words, Rogue B can HIPS with a -20 penalty in certain conditions (if she was hidden before the ranged attack and was at 10 feet away). But is she fails her hide check, she apparently cannot hide again.
Rogue A cannot hide again once Target spots her, since she is visible and in plain sight.
As an extrapolation of the sniping rule, I'd allow anyone to hide in plain sight while being observed at a -20 penalty as a move action if they have cover or concealment and are at least 10 feet away from all observers.
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RAW again...
In contrast...
A ranger with the HIPS (Ex) ability can hide while being observed in natural environments at no penalty, but only if the ranger has concealment or cover. So if in a forest with shadowy illumination, the ranger can attack while hiding at a -20 penalty. If the ranger is spotted, he can make a new hide check (as a move action or combined with a move action) at no penalty. Likewise, he can hide after sniping at no penalty. (Rambo lives!)
A shadowdancer with the HIPS (Su) ability can hide while being observed as long as she is within 10' of shadow, even without concealment or cover. So if within 10 feet of a target that casts a shadow, she can attack while hiding at a -20 penalty. If the shadowdancer is spotted, she can make a new hide check (as a move action or combined with a move action) at no penalty. Likewise, she can hide after sniping at no penalty.