"Struggle" is what the spider web tattoo symbolizes -- struggling in the ‘web of life’. And struggle in a spider's web implies capture, and the multiple strands of the web itself is often a metaphor for bars. Prison bars. In the West those bars usually represent criminal activity. In the East, or Communist Russia, prisoners may be criminal or political. And when captured, our most primal instinct is to seek escape, no less than the moth or the fly. But of course a spider's web is notoriously difficult to escape from.
As a tattoo design, a spider web can also express other forms of "struggle". It may be the struggle against the dictatorship of drugs, or the feeling of being caught in a political, social or economic system you can't escape, or an even more general sense of wishing you were never born. For the wearer of the spider web tattoo, it likely means something very unique, very personal -- it means what they want it to mean.
Spider web tattoos have a dark history going back some seventy years, when Aryan, or White Supremacy gangs reportedly wore the spider web tattoo as a form of racist braggadocio, reportedly a sign that they had terminated a visible minority. The spider web became de rigeur in prisons, with each ring of the web representing time spent inside, or how many ‘prey’ have been ensnared in the wearer’s web. You might spot one on an elbow, sometimes on the back, or on the side of the neck, emerging from behind the ear, and more rarely, on the face. It has served as a billboard that the wearer is in for murder, or as a warning to enemies to keep their distance -- especially one worn on the left elbow -- which advertises the web-wearer as one who has a deadly weapon tucked away. A more philosophic prisoner might use the spider web as a reminder that they aspire to freedom, to escape the web from which they have become entangled. For some, say those with a 'Gallow's' sense of humour, the spider's web design can be taken more literally, almost as a joke, a statement to the world that goes; "Hey, I've been locked up for so long, I've got cobwebs."