Recently, a new subject known as the Social Internet of Things (SIoT) has been presented based on the integration the Internet of Things and social network concepts. SIoT is increasingly popular in modern human living, including applications such as smart transportation, online health care systems, and viral marketing. In advertising based on SIoT, identifying the most effective diffuser nodes to maximize reach is a critical challenge. This article proposes an efficient heuristic algorithm named Influence Maximization of advertisement for Social Internet of Things (IMSoT), inspired by real-world advertising. The IMSoT algorithm consists of two steps: selecting candidate objects and identifying the final seed set. In the first step, influential candidate objects are selected based on factors, such as degree, local importance value, and weak and sensitive neighbors set. In the second step, effective influence is calculated based on overlapping between candidate objects to identify the appropriate final seed set. The IMSoT algorithm ensures maximum influence and minimum overlap, reducing the spreading caused by the seed set. A unique feature of IMSoT is its focus on preventing duplicate advertising, which reduces extra costs, and considering weak objects to reach the maximum target audience. Experimental evaluations in both real-world and synthetic networks demonstrate that our algorithm outperforms other state-of-the-art algorithms in terms of paying attention to weak objects by 38%-193% and in terms of preventing duplicate advertising (reducing extra cost) by 26%-77%. Additionally, the running time of the IMSoT algorithm is shorter than other state-of-the-art algorithms.