I do not deal with insurance law, but I would assume that the condition of the title could matter to an insurer. This would definitely be an issue if the car is in an accident and there is the possibility that the car had been damaged previously.
A salvage title usually arises when an insurance company declares the car "a total loss" and either replaces it or pay the insured the value of the car at the time of the damage. Such cars can be repaired, licensed and driven, and there are repair businesses who specialize in this, but the rule of thumb is that the value of the car as compare to an identical one that has a clean title would 1/2. The problem is that this can happen on other states and you will not be able to trace it without some real effort. And online companies that claim to provide a complete history, often are incomplete.
As mentioned previously, a salvaged title usually occurs when a car has been declared a total loss.. Such a car cannot be driven legally unless the vehicle is repaired and a rebuilt title is issued. Before a rebuilt title can be issued, the vehicle usually has to be inspected by some authority (the state patrol in Washington). However, due to the vehicle's history it is common for insurance companies to either charge higher rates to insure such a vehicle or to refuse to insure it at all. So before purchasing such a vehicle, be sure to check with your insurance company to find out what the rates will be.