Just as any hobby, whether Github or Stack Exchange, think about how it reflects on you. There are many questions here which would not be good reflections on their posters - a lot are "my boss/coworkers suck" type.
Those would not reflect well on you, but neither would a profile of trivial questions on Stack Overflow (or more scandalous content elsewhere online or on your Facebook).
However, some people write good content. In these cases it can contribute positively to your personal brand. There are three key pieces in this puzzle:
- What the quality of your content is
- What its content actually is
- How you present it
The first two are discussed above. The latter is probably the most interesting piece of this puzzle.
But realistically even if you are the top contributor here, the overall impact a site like this will have is pretty minor, unless you can correlate it to actual experiences in your interview/resume. The answer to how a site like this affects personal brand is more often than not, "no one cares" - my 77,000 reputation here is just fairy dust for 99% of interviewers.
It's just one little niche site in a large internet and a site that is likely unknown to most people. If anything the way you could brand experience here is "I write answers for a site like AskAManager" because it is more popular and well known.
I have talked about my experiences here in a more generic sense, saying that I write online and answer questions which helps me to be better at communicating. This is much more impactful when "marketing" myself because it is a valuable and tangible skill to talk through with an employer.
I think this is fairly good advice for any hobby - unless you are forcing conversation make sure to discuss the skills and benefit you actually get from your hobby. Stack Exchange is no different in this regard. But be aware you might get asked "what's your profile?" if you do say you write on it. Don't have a pile of "my boss SUCKS" questions..
All that being said, it is advisable to ask questions you would be embarrassed to have publicly associated with you either with a second account or anonymously.