Like helping to find a bug, discussing about how to setup an application for a certain use case or anything like that? Answering questions on Stack overflow is an example but is that the best way?

Generally the best way to help out is to do a thing that’s needed and that you can figure out how to do. Your list includes a bunch of good options, and I’ve been thanked for doing all those things at one point or another. Some common growth paths include:

1. Using the software
2. Encountering bugs, problems, or small opportunities for improvement.
3. Discussing those informally in forums and helping people find workarounds.
4. Identifying some of those issues as common things other things experience as well, so filing bugs for them with clear explanations and links to related forum discussions.
5. Reading source code to better understand bugs.
6. Discussing potential fixes in developer bug threads (or in GitHub or whatever).
7. Submitting small fixes for simple bugs as pull requests.

Another path might be:

1. Using the software and reading forums/docs for help.
2. Answering basic questions on forums, looking to old threads and relevant docs.
3. Learning about common questions.
4. Writing blogs or forum posts about common questions.
5. Submitting improvements to official docs to clarify common areas of confusion.

There are other paths as well, the main thing is to use a thing so you learn about it and then use that knowledge to make it a little easier for the next person. Good luck!

I don’t think titles directly transfer between companies, and yet the industry allows it. It’s a very useful tool for advancement.

This may be true on some corners of the industry, but at the more competitive end (both in terms of competitive pay, and a competitive pool of candidates)… I believe it’s common to relevel on hire. I’ve seen folks go from director to senior and from senior to junior at my org. The candidates being offered those seemingly big “demotions” often seem to be somewhere between unphased and enthusiastic about the change, presumably because the compensation package we offer at the lower level beats what they were getting with an inflated title and because they know their inflated title is nonsense and they’re frustrated with the other aspects of organizational dysfunction that accompany title inflation at their current company.

What you say is real, and sometimes a promotion in one org can help bridge you into an org that would have been hard to get hired into as a junior, or harder to get promoted in. It’s not without risk though. All things being equal, I’d much rather spend my time working on a strong team and learning a lot and being challenged than to be in a weaker org that’s handing out inflated titles. Getting gud isn’t a guarantee of advancement, but it’s at least as reliable over the long haul as title inflation.