Compare Online Course Platforms for Self-Directed Learning

You want to learn a skill online and the platforms all promise the world, from structured university courses to a thousand half-finished Udemy tabs. This compares the platforms for your specific goal, sorting structured paths from one-off videos, so you pick the format that actually gets you to a useful level rather than another certificate gathering dust.

<context>
You want to learn {SKILL_AREA} through an online course. You have seen options on [Coursera / Udemy / LinkedIn Learning / edX / Skillshare / YouTube / other] and are unsure which platform and format will actually get you to a useful level of competence rather than just a certificate.
</context>

<task>
**Compare the platforms for your specific learning goal:**
1. Distinguish between platform types: structured degree-level, professional certificates, project-based, and informal video
2. Evaluate each option against four criteria: depth, credential value, time commitment, and cost
3. Explain the completion-rate problem with online courses and how to design around it
4. Recommend the best option for your skill area and intended use
5. Give a study structure for the recommended course that maximises completion and retention
</task>

<output_format>
- Platform comparison table: Platform | Best for | Depth | Credential value | Cost
- Completion-rate problem explained (2-3 sentences)
- Recommendation with rationale
- Recommended study structure (weekly commitment, milestones, accountability method)
</output_format>