Most questions about tanking in Star Trek Online start from habits learned in other games. This page answers them one at a time, in the order people usually ask.
Mostly no. There is no strong set of taunts that force enemies to attack you, and no way to redirect damage from a teammate. What you have is threat, a measure of how much the enemy chooses to shoot you, and a handful of tools that raise it.
There are a few real taunts, but they are tied to specific ships or traits. Hard taunts are unconditional and time based, such as Diversionary Tactics from the Strategist specialization, the Chronotachyon Capacitor console, and the A Budding Alliance trait. Softer ones, like placate effects, only work under conditions.
The community guides define threat as how much the enemy shoots at you compared with your nearby allies within 10 kilometers, measured as a percentage of incoming attacks. A good tank holds 75% or more of that share, and an excellent one holds above 90%.
To make that concrete, suppose four enemies make 400 attacks over a fight against you and your allies in range. A tank at 75% takes 300 of them and a tank at 90% takes 360. Those figures are illustrative, but the gap of 60 attacks is 60 hits that would otherwise land on your teammates.
These are the sources the community guide lists:
The guide does not say exactly how these combine, so treat the list as a shopping list rather than a formula.
With so few direct taunts, damage output is what builds threat, which is why the community guide states that tanks need to do damage. Area attacks are the tool, and Fire at Will is the standard one: it fires at several enemies inside your weapons' firing arc, so it builds threat against all of them at once. That is also why tanks favor beam arrays and their wide arcs, as covered in The Anatomy of a Meta Energy Build.
A heavy tank puts survivability and damage first and can work alone in any content and with any team. The USS Bedivere and Chronos builds are examples. A support tank adds debuffs and buffs for allies while keeping basic survivability, and does its best work on parse maps with capable damage dealers. It adds less to raw completion speed and more to its teammates' numbers.
As a rough expectation, a heavy tank typically deals 25% to 35% of the combined damage of the non tank players while holding threat. With four teammates each doing 500,000 DPS, 2,000,000 in all, that comes to about 500,000 to 700,000 DPS from the tank, using those illustrative figures.
Holding threat means taking hits, so a tank needs three kinds of defense working together: burst heals from consoles and active traits, sustained healing from gear, traits, and bridge officer abilities, and damage resistance. The community guide adds that bonus damage resistance rating scales better than standard damage resistance rating.
Two bridge officer abilities count as mandatory. Reverse Shield Polarity III in a Commander Engineering seat converts a share of incoming energy damage into shield health and has a 120 second base cooldown. Suppression Barrage III in a Commander Command seat weakens a target's damage, speed, turn rate, and accuracy. For seating, the community ranks Command at Commander first, then Miracle Worker, then Temporal, as explained in Specialization Seating Explained. Recommended gear includes the Discovery three piece for shield regeneration and Energetic Protomatter Matrix Infuser tactical consoles, and Selecting the Right Deflector, Engine, Core, and Shield explains those choices.
If your ship has them, cruiser commands are team auras: Weapon System Efficiency, Shield Frequency Modulation, Strategic Maneuvering, and Attract Fire. Which ones you get depends on the ship type, but a standard cruiser has all four. Only one can be active at a time, and they must be reactivated whenever you change maps or respawn after dying. Forgetting to reactivate Attract Fire after a respawn is one of the easiest ways to lose threat without noticing.
The Chronos build published by STO BETTER is a heavy tank on a Temporal Dreadnought Cruiser. It runs Threatening Stance, Fire at Will as its firing mode, the Emergency Weapon Cycle, Entwined Tactical Matrices, and History Will Remember starship traits. For defense it uses Reverse Shield Polarity III, Bio-Molecular Shield Generator, and Chronotachyon Capacitor. Its author reports holding roughly 75% to 90% of the team's incoming attacks on Elite maps, and using Photonic Officer I for cooldown management. Those figures are the author's own and depend on the map and the team.
On Advanced difficulty, a tank is nice to have but not essential for players with reasonably capable builds. On Elite, certain maps practically require one to finish. If you are unsure, read Survivability: Hull, Shields, and Resistance first, then plan the build in the Build Planner. Once you have flown it, the Damage Taken section of the Combat Log Reader shows how much you are actually absorbing, and the /CombatLog command tutorial explains how to record that run.