The key difference between Type 1 and Type 2 SCD lies in handling changes. Type 1 updates the current record, overwriting old values, while Type 2 creates a new record for each change. This preserves historical data, allowing analysis of data changes over time.

Common strategies for implementing superclass-subclass relationships in relational databases include Table-per-hierarchy, Table-per-subclass, and Table-per-concrete-class. Each strategy has its own advantages and considerations based on the specific requirements of the database model.

Denormalization can improve performance in this scenario by introducing redundancy through the combination of tables, reducing the need for JOIN operations when loading user feeds. This helps streamline queries and enhance retrieval speed.

In conceptual schema design, the emphasis is on creating a high-level representation of the data model, focusing on the structure and relationships of entities. It abstracts away implementation details to capture the essence of the data.

The replication factor in NoSQL databases plays a crucial role in maintaining data consistency by affecting read and write performance. A higher replication factor enhances data availability and fault tolerance but may introduce higher latency in write operations due to synchronization among replicas. It is a trade-off that administrators need to consider based on the desired level of consistency and performance.

A NoSQL database would be most suitable for this scenario. NoSQL databases, especially document-oriented ones, are well-suited for handling large amounts of unstructured or semi-structured data, making them ideal for storing user-generated content like posts, comments, and likes in a social media platform.

Version control facilitates the management of incremental changes made to data models over time. It tracks modifications, maintains a history of revisions, and enables collaboration while ensuring the integrity and consistency of the data modeling process.

Microsoft Visio offers an advantage with its integration with Microsoft Office applications. This allows users to seamlessly incorporate their database diagrams into other Office documents, fostering better communication and documentation. Its versatility makes it a preferred choice for those already using Microsoft tools.

Key-Value Stores are often preferred for their Flexibility and Performance. The flexible structure of key-value pairs allows for easy adaptation to different data types, and their performance benefits from the simplicity of direct key-based access.

In NoSQL databases, Versioning is a mechanism used to detect and resolve conflicts in data versions. Each update is associated with a version, and conflicts can be identified and resolved based on these versions, ensuring data integrity in distributed systems.