What was the primary challenge the co-founders faced in the early days of YouTube?

In the early days of YouTube, the co-founders faced several primary challenges:

1. **Bandwidth and Storage Costs**: Hosting and streaming videos required significant bandwidth and storage. As YouTube grew rapidly, managing these costs became a major challenge. The infrastructure needed to support a massive and growing number of video uploads and views was both complex and expensive.

2. **Monetization**: Finding a sustainable revenue model was crucial. While YouTube attracted millions of users, figuring out how to monetize the platform effectively and attract advertisers was a significant challenge. This issue was partially addressed after Google acquired YouTube, integrating it with Google's robust advertising infrastructure.

3. **Content Moderation**: Managing the vast amount of user-generated content and ensuring it complied with legal and community standards was challenging. The platform needed to develop policies and systems to handle copyright issues, inappropriate content, and user complaints.

4. **Scalability**: Scaling the platform to handle increasing traffic and data was technically demanding. The co-founders had to continuously improve their infrastructure to accommodate growing user numbers and video content.

5. **Competition and Market Positioning**: Initially, YouTube was one of several video-sharing sites. Establishing itself as the dominant platform required distinguishing it from competitors and building a strong user base and brand.

Despite these challenges, YouTube's innovative approach, combined with early viral content and user engagement, helped it overcome these obstacles and establish itself as a leading video-sharing platform.