A main factor in selecting eCommerce platforms is the level of scalability they offer. Businesses need platforms that can grow alongside their operations, accommodating increased traffic and transactions as their customer base expands. Other important factors include user-friendliness, payment gateway options, integration capabilities, and built-in marketing tools. Security features, such as compliance with payment standards and data protection regulations, also play a crucial role. Ultimately, the platform must meet the unique needs of the business for successful online operations.