Congress Vice-President Rahul Gandhi on Saturday took a dig at Prime Minister Narendra Modi for his comment on civil servants, provoking Union Textiles Minister Smriti Irani to tweet: "Look who is talking about being overrated."Responding to Modi's caution to civil servants not to use social media for self-promotion, Gandhi tweeted on his official Twitter account: "Leading by example is clearly overrated." He attached an article in an English daily on Modi's comment.Irani returned the fire with her own tweet.Addressing a function on the Civil Services Day here on Friday, Modi said anonymity of civil service had been a strength but this appears to be getting weaker.