Illinois is not adding customers. The state had an estimated 12,719,141 residents in July 2025, and the resident population was down 0.8% from the 2020 base. Growth here comes from taking share and from selling beyond the state, so websites that explain what makes a firm different, and search content aimed at buyers in other states, carry extra weight.
Expertise slightly outnumbers retail. The 2023 count found 37,946 professional, scientific and technical services establishments and 35,801 retail trade establishments, among 322,415 employer establishments in total. Consulting, engineering, legal, accounting and design work is usually bought after careful online research, which rewards detailed service pages and articles that answer real client questions.
Small firms dominate the count: 85.4% of employer establishments had fewer than 20 employees. When small firms compete with larger ones, a fast, specific website is one of the few places where size matters less.