Ask HN: CS Researchers, why did you choose your subfield and niche?

I'd be a little careful with your one-line dismissals of fields. Each field has hundreds of people dedicating their entire lives into it. It'd be offensive to them that someone who hasn't even done any research to think they can judge an entire field like that. Imagine a high school student who took a community college course and saying "University juniors don't know anything. I discovered that they just copy from Wikipedia." The advice in this thread is a great starting point.

Echoing what a lot of other posters are saying, I would strongly recommend considering advisor/group fit. Of course, research field also matters; it seems like you don't really like networking/security that much, so feel free to steer clear of those disciplines. However, let's say you meet an awesome AI prof, and their work is of moderate interest - that seems like a recipe for a good time, even if the field is saturated/there's an AI winter in our future.

Anecdotally, my first research position was the result of getting my last-choice internship for that summer. I thought I would hate it and was planning to quit after the summer. My advisor was incredible, and I ended up working in that lab for 3 years. That field (human-computer interaction) is now my primary discipline!

I chose to focus on computational biology because I had an amazing professor that I wanted to work with. That being said, an amazing professor != amazing advisor... something I discovered when trying to finish my PhD and he decided to take a sabbatical to Kenya to do missionary work :(.

I got enough statistics and machine learning experience in graduate school to be doing machine learning research now as part of the defense industry. Even if machine learning seems like it might be too hot to touch, it will aid you in any number of jobs you could have in the future: automation, data science, etc. It really is perhaps the easiest sub field to cross disciplines. I've always been a PC gamer and the TD-Gammon paper really pushed me forward in my desire to do machine learning -- check it out, its a classic (https://www.bkgm.com/articles/tesauro/tdl.html).

Don't be pessimistic you will always find your spot no matter what. Just follow your interest. Review again the papers and research your seniors do and see which one interests you most. Choose something that you like to do all day.

One more small piece of advice: try to get on whatever mailing lists you need to to start attending the research talks at your college or university. (Some of this might be harder in the age of Zoom/economic collapse, but still...) This can vary based on what type of college you are attending, but if you are at a research university, there can be a lot of these: departments or research groups may have seminar series/colloquia, and then every doctoral student is going to have a public defense, and every job candidate who wants to be a professor is going to do a public "job talk," and at some places, every junior-faculty member who wants to get tenure has to do a "tenure talk," etc. These are almost always just open to anybody who wants to come.

So there may be a lot of opportunities for you to see a diverse range of talks (many of which will be intended for a general CS audience, at least for most of the talk) and get a sense of what people find exciting/interesting/achievable on various frontiers of CS research in different subfields. For the job talks at least, the candidate is sometimes giving the best talk they will ever give in their life, so it's possible to see something compelling in a subfield that you might not otherwise glimpse just by taking a course or something. And (this is more applicable to real-life talks) if you like you can usually go up to the speaker afterwards to ask them something privately and usually presenters are flattered to have somebody interested. Or if somebody in the audience asks a question that you find interesting, same thing. This might seem awkward and I know it might not seem this way, but it's hard to truly embarrass yourself by showing interest or enthusiasm -- you're in college! (As a student, I once found myself in a conversation with some random dude about the Gamow/Stern/Knuth elevator results after we both waited for the elevator for a long time after attending a talk at MIT, and when we were done I was like, "By the way, who are you?" and he looked a little surprised and was like, "Uh, I'm Butler Lampson.")

If you're not at a research university, that may decrease the number of random research talks you can show up to, but it also suggests the faculty will be much more eager to collaborate with undergraduates and involve you in a material way in their research projects.