[nikolaj]

If you work in a related field (e.g. digital agency, web development company, devops), check to see if you signed an employment agreement or confidentiality agreement.

Read it carefully, then imagine if you did a side project relating to what your current expertise is, for Automattic on the weekends.

Then ask yourself if it would violate your agreement.

It might not, or you might not have such an agreement, but we do and I think (although IANAL) this does not sit well with that agreement.