Our human resources department likes to use this term. I've raised with them the idea that track records are hardly provable. They often edit job ads, inserting the term where we're looking for demonstrable research output or work experience in a field. The first is much easier to demonstrate than the second, especially in the context of commercial-in-confidence work in some employment situations.
When assessing proven track record in a particular field, I look for the following:
- Peer-reviewed publications
- Teaching experience, including PhD supervision
- Competitive grant success
- Group (ie., department, lab, etc.) leadership
- Esteem measures (ie., fellowship in a learned society, awards)
For an early-career applicant, the last three items above may not have been achieved yet.
To answer your question directly, I would consider blogs, discussion forum participation and SE membership to be peripherally related to the track record except in one particular case: when the job involves a strong component of social media engagement. For example, I might have an opening for an academic whose administrative load included the development and implementation of the Department's social media strategy.
Finally, your use of the word "programs" is vague. If you've developed software or applications in the field, then I would classify this as research-related output. If you mean you developed educational videos and posted them online, then these might be classified as teaching output. If you mean you've organised programs of activities, this might be relevant, too. unfortunately, for every interpretation that shows relevance, there are many that may be irrelevant.
Finally, I suggest that you seek clarification from the contact person listed in the advertisement about the way you can best meet their criterion of "proved track record". Tailoring your application to the needs of the assessors is an important aspect of the submission process.
Good luck to you.