There are many influential books in many fields that say they're using semiotics. But I haven't yet found the semiotics to do anything, or to introduce any new concepts. All I see is that it lets them express their thoughts in longer but more stereotyped sentences.

For instance, instead of saying, "The Serbians said Albanians were dirty, violent, primitive, and greedy," they would write, "The significations given to the figure of the Albanian in Serb discourse is characterized by condensed images of Albanians as dirty, violent, primitive, and greedy."

Introductions to semiotics talk about linguistic functions like metaphor or the relationship between an object and its name, but they don't say anything you didn't already know. They won't help you understand metaphors better. They'll make distinctions and then argue about them interminably without ever grounding those distinctions in reality. Like this:

Lacan's reformulation of the Saussurean sign provides a crucial turn in the theory of meaning: rejecting the idea that signifier and signified are inextricably linked in the sign, ... he argues that they form distinct planes.... Lacan establishes the difference between signifier and signified: metonymy, or displacement, is found 'on one side of the effective field constituted by the signifier', while the other side is linked to metaphor or condensation. The signifier operates associatively, displaced along a chain of signifiers into which the signified emerges to arrest the flow... As a result, meanings change, an effect of the 'sliding of the signified under the signifier' in which the latter predominates.

I don't think that means anything. If it meant something, semioticians could take actual sentences, and then show how the two opposing views provide different interpretations of those sentences, and argue that one interpretation is better. I haven't seen them do that.