Plagazon

A Plagazon (also known as a Poisonzon) is an Amazon build that specializes in the Plague Javelin and Poison Javelin skills. It is a less common alternative to the Thunderfury build. It relies less on synergies than the Thunderfury, which leaves you with more wiggle room for passive skills. Not all players take poison damage seriously, but its potential to do massive damage can't be ignored.

Stat Distribution
Strength: Enough to use your gear. Don't put in more than you need.

Dexterity: Enough that you have maximum block.

Vitality: Anything else.

Energy: Should be left alone. Equipment and potions will cover this.

Maxed Skills:
20 Plague Javelin - This is your bread and butter. Works best for crowd control.

20 Poison Javelin - Provides synergy for Plague Javelin and is useful when not fighting groups.

Other Important Skills:
1+ Valkyrie - Your handy-dandy meat shield. She helps keep enemies away from you.

1+ Decoy - Another meat shield, monsters are particularly attracted to decoys.

1-15 Dodge, Avoid, and Evade - Makes you significantly harder to hit.

1+ Critical Strike - Gives a chance of doubling your damage. This doesn't work with poison, so it's not as important as the other skills.

1+ Penetrate - Increases your Attack Rating, which makes you hit more often.

5+ Pierce - Creates total havoc in crowds, doing even more damage.

1+ Lightning Fury - Optional, and makes this build more of a hybrid.

All passive skills should be taken at least once. After that, you can decide where to distribute your points. Lightning Fury is useful for PvP and for Poison Immune monsters.

Immunities
Plagazons have the advantage of running into fewer monsters immune to their damage than say, the Sorceress. Some monsters, usually Undead and constructs are immune to poison. In Nightmare and Hell this number increases significantly, and there are even some immune to both poison and lightning damage. On Hell difficulty, it may be a good idea to get a Rogue Archer with Fire Arrow or Cold Arrow in case you run into Poison Immune Monsters (or poison and lightning immune if you're a hybrid).

Strategy
You can greatly increase your effective DPS by poisoning a group of enemies, then running off to find another group of enemies (at the same time as waiting for the first group to die), then running off to find another group, etc. until you circle back and pick up the death drops of the first group. This works better with Poison Javelin rather than Plague Javelin, since at higher /players settings Plague Javelin might not deal enough total damage to kill monsters (its main advantage is the larger area and higher DPS, while Poison Javelin has higher total damage dealt but takes a lot longer to kill enemies), but Poison Javelin will almost assuredly kill most monsters and champions before it wears off.

Use Decoy as needed to keep the poisoned mobs at bay.

This strategy keeps your mana usage low while boosting your DPS to match those of more powerful builds, but is not viable when you are in a party since most players will prefer to have a single pass over the area rather than leaving one group to suffer poison while you search for the next group to poison.

Tactics
Directly aiming at the mobs is sub-optimal unless you are using Plague Javelin and have a high-level Pierce. Until you raise your Plague Javelin and Pierce levels, you should instead aim off to the side, leaving a trail of poison clouds, then run to position the poison clouds between the mob and yourself.

As poison takes time, make good use of Decoy and Valkyrie to keep mobs off you until the poison wears off or the monsters die.

Use Decoy to scout an area and attract monsters you can then throw a Plague Javelin at.