Which of the following is a characteristic of Salesforce to Salesforce integration?

Salesforce to Salesforce integration is indeed characterized by being a free service. This integration allows different Salesforce organizations to share data with one another without incurring extra costs, provided that both organizations are using Salesforce. This integration simplifies collaboration between businesses by enabling them to share records like accounts, contacts, and opportunities directly.

While some integration methods may involve additional costs or necessitate third-party tools, the native Salesforce to Salesforce feature is designed to enhance connectivity and ease of data sharing without requiring paid subscriptions. This makes it particularly valuable for organizations seeking a cost-effective solution for collaboration.

Options mentioning real-time synchronous updates, requiring a paid subscription, or manual data transfer do not accurately reflect the core characteristics of this integration, as the service is focused on simplified sharing and connectivity.