Definition
ChatGPT is OpenAI's conversational AI assistant, available on the web and in desktop and mobile apps. OpenAI said at DevDay on September 29, 2026 that ChatGPT had 1.2 billion weekly users, up from the 900 million weekly users and more than 50 million consumer subscribers it reported in February 2026.
ChatGPT launched on November 30, 2022 as a single chat window. It is now a set of connected surfaces: Chat for everyday questions, built-in web search (see ChatGPT Search), deep research for long cited reports, a Work tab and Codex for longer agentic tasks, third-party plugins, and, announced at DevDay 2026, always-on agents called Dots for some paid plans. The standalone ChatGPT Atlas browser was retired in August 2026 and its agentic browsing moved into the ChatGPT desktop app (see ChatGPT Atlas).
Since October 7, 2026 the Chat experience runs on GPT-6 on every plan: GPT-6 Sol for Plus, Pro, Business and Enterprise, and GPT-6 Luna for Free and Go. OpenAI's GPT-6 announcement lists two changes that matter for search visibility. The model can start answering while it is still reasoning, and it 'makes better decisions about when to look something up.' GPT-6 also introduced Intelligent UI, where an answer can contain charts, maps, forms or small interactive tools instead of only text. Work and Codex keep their own model versions, and OpenAI announced GPT-6.1 Sol for developers at DevDay 2026. For the model family itself, see GPT and reasoning models.
The consumer plans are Free, Go ($8 a month in the US), Plus ($20) and three Pro tiers at $100, $200 and $500 a month. Business seats start at $20 per user per month on annual billing, and Enterprise is priced through OpenAI's sales team. Since February 9, 2026, OpenAI has shown labeled sponsored ads below answers to logged-in adult users on Free and Go, starting in the US and expanding during 2026 to markets including the UK, Japan, Brazil and 31 European countries. Plus and higher plans are ad-free, and OpenAI states that ads do not influence answers.
For brands, ChatGPT matters because a large share of product research, vendor shortlisting and how-to questions now starts there. When an answer needs current information, ChatGPT searches the web, usually with several rewritten queries (a query fan-out), and cites a small set of pages. Promptwatch's data on average sources per response shows ChatGPT typically cites about five sources per web-search answer, so each citation slot is contested. Citation behavior also shifts with model and retrieval updates: average citations per response fell by about 27% around the GPT-5.3 rollout in March 2026, and reddit.com's share of ChatGPT citations dropped from about 4% to 0.5% on August 14, 2026.
Getting cited starts with access. OpenAI documents separate crawlers for search (OAI-SearchBot), training (GPTBot), user-triggered fetches (ChatGPT-User) and ad landing pages (OAI-AdsBot), covered in OpenAI crawlers. After that, the work is content that answers specific questions in self-contained passages, third-party coverage that names your brand, and regular updates so pages stay eligible. Teams measure progress by running a fixed set of prompts on a schedule and tracking brand mentions, position in the answer and citation share, then checking AI-referred traffic in analytics. The practical playbook is in ChatGPT optimization and our guide to how ChatGPT searches the web.
Examples of ChatGPT
- A B2B payroll vendor runs 150 buyer prompts through ChatGPT every week and finds it is named in 38% of answers but cited from its own domain in only 6%, so it rewrites its pricing and comparison pages as short, quotable sections.
- After GPT-6 became the default Chat model on October 7, 2026, a travel publisher compares a month of answers before and after the switch to see whether fewer prompts trigger web search for its destination guides.
- A DTC skincare brand notices ChatGPT answers on free accounts now show a sponsored product below the response and tracks those ads separately from organic mentions so paid and earned visibility are not mixed in reporting.
- A SaaS company sees its referral traffic from chatgpt.com rise after a third-party review site that ChatGPT cites often adds the company to its 'best tools' roundup.
- A developer-tools startup checks its server logs and finds OAI-SearchBot blocked by a CDN bot rule, which explains why ChatGPT mentions the product from training data but never links to its docs.
