Simple

text-shadow: 25px 50px blue

Blur

text-shadow: magenta 0 0 3px

Multiple

text-shadow: 4px 4px blue, 8px 8px green, 12px 12px yellow

Spread

text-shadow: 0 0 0 5px magenta

Spread and blur

text-shadow: 0 0 10px 5px magenta