While WPSE is perfectly friendly to commercial entities and professional reputation building (most of my own professional reputation are WPSE points :), it is still delicate balance between individual participation and explicit or implicit promotion.
This is not complete turn key guide to such participation, but from my experience I can identify several foundational aspects, which are very important to get right for having and maintaining good connection with stack's community.
Historically company profiles and excessively company-themed identities are frowned upon by community. People prefer to communicate with other people rather than faceless corporate entities.
- individual account
- professional/employer information in profile
- disclosure in content where appropriate (for the sake of openness rather than self promotion)
Not [very] appropriate:
- company and especially shared account
- professional/employer signatures in content (signatures are forbidden in general)
- excessive mention of company where irrelevant
The content (questions and answers either) should strive for same high quality standards and wide applicability.
For hypothetical question (self or third party posted):
How to resolve this issue with server configuration for WordPress?
From my experience [at our company doing relevant things] users commonly encounter this issue because [...] and I recommend to [...]
At our company we are solving this issue via [open source] solution we created, which you can make use of by [...]
Our hosting has unique super-duper feature that does this (AND brews coffee).
There are essentially no formal rules what is spam or excessive self promotion to be precisely abided by. Community determines instances of such by gut feeling and, believe me, community is way better at it than any set of rules or code analysis can possibly be.
Contribution that is genuinely helpful and open is rarely misunderstood.
However sometimes dialog and discussion is what it takes, so involvement here on meta is vital - both reactive (resolving inquiries or complaints from community) and proactive (asking community for information or opinion).