Organization and Description of Business	12 Months Ended
Organization and Description of Business	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business System1, Inc. and subsidiaries (the "Company", "we", "our" or "us") operate an omnichannel customer acquisition platform, delivering high-intent customers to brands, advertisers and publishers. We provide our omnichannel customer acquisition platform services through our proprietary responsive acquisition marketing platform ("RAMP"). Operating seamlessly across major advertising networks and advertising category verticals to acquire end-users, RAMP allows us to monetize such end users through our relationships with third party advertisers and advertising networks ("Advertising Partners"). RAMP operates across our network of owned and operated websites and related products, allowing us to monetize user traffic that we source from various acquisition marketing channels, including Google, Meta, Outbrain, and TikTok. RAMP also allows third party advertising platforms and publishers ("Network Partners"), to send user traffic to, and monetize end user traffic on, our owned and operated websites or through our monetization agreements. Our primary operations are in the United States, and we also have operations in Canada and the Netherlands. Operations outside the United States are subject to risks inherent in operating under different legal systems, as well as various political and economic environments. Among these risks are changes in existing tax laws, changes in the regulatory framework in foreign jurisdictions, data privacy laws, possible limitations on foreign investment and income repatriation, government foreign exchange controls, exposure to currency exchange fluctuations and employment laws impacting foreign employees. We do not engage in hedging activities to mitigate our exposure to fluctuations in foreign currency exchange rates. On June 28, 2021, we entered into a Business Combination Agreement (as amended on November 30, 2021, January 10, 2022 and January 25, 2022), ("Business Combination Agreement") by and among us, S1 Holdco, LLC ("S1 Holdco") and Total Security Limited, formerly known as Protected.net Group Limited ("Protected"). On January 26, 2022 ("Closing Date"), we consummated the business combination ("Merger") pursuant to the Business Combination Agreement. We, through Total Security Limited, formerly known as Protected.net Group Limited ("Protected"), also provided antivirus software solutions, offering customers a single packaged solution that provides protection and reporting to the end user. On November 30, 2023, we completed the sale of Protected, including our antivirus and consumer privacy software solutions, pursuant to the terms of a share purchase agreement ("Share Purchase Agreement"). Pursuant to the Share Purchase Agreement, Just Develop It Limited ("JDI"), one of our significant shareholders, which is principally owned and managed by certain members of the Protected management team ("Purchasing Parties"), acquired all of the outstanding preference and ordinary shares ("Protected Disposition") of Protected for total consideration comprised: (a) $240.0 million in cash, subject to certain adjustments, (b) the return and subsequent cancellation of approximately 29.1 million shares of our Class A common stock, par value $0.0001 per share, owned by the Purchasing Parties and (c) confirmation from JDI, Protected and the Protected CEO that the financial performance benchmarks related to certain contingent earnout payments (the "Protected Incentive Plan") based on the future performance of Protected’s business in an aggregate amount of up to $60.0 million contemplated by the Business Combination Agreement related to the Merger, will, as a result of the Protected Disposition, no longer be achievable. The results of operations of our Protected business prior to its sale are presented as net loss from discontinued operations in our consolidated statements of operations for all periods presented (see Note 17, Discontinued Operations). On August 1, 2024, we undertook a corporate reorganization, the result of which was that all of the assets and business operations of the company are now held by System1 Holdings, LLC ("System1 Holdings"), a newly formed intermediate holding company of which we maintain the controlling interest and in which the non-controlling interest is owned by the holders of our Class C common stock. Following the corporate reorganization, (a) System1 Holdings now owns 100% of S1 Holdco, LLC ("S1 Holdco"), the previous intermediate holding company with the non-controlling interests, and 100% of S1 Media, LLC (“S1 Media”), another new subsidiary formed in connection with the corporate reorganization, (b) S1 Media holds the assets and business operations associated with our owned and operated products businesses, which include CouponFollow, Startpage and Mapquest, and (c) S1 Holdco holds our remaining assets and business operations associated with our digital advertising businesses, including our proprietary RAMP platform. S1 Holdco and its subsidiaries remain obligors and guarantors under our Term Loan and 2022 Revolving Facility, and System1 Holdings and S1 Media are not parties thereto. We have two reportable segments: Owned and Operated Advertising and Partner Network (see Note 14, Segment Reporting).