You can put your thumb over the end of a hose and it’ll cause water to come out faster, but it kind of masks how big the original opening actually is. The niche thing is like that – you can iterate more rapidly, get more pointed feedback, and generally create value faster by focusing on a core group. But it masks the data about the size and applicability to your total addressable market. That’s the tradeoff.
I would encourage you to think about your target market in terms of user personas. What are their titles, what do their jobs consist of, and how many of them are out there. Make sure that universe is large enough and the problem you’re solving for them is significant enough. THEN you can layer on additional segmentations such as industry, geo, etc, to give you a more focused market and messaging – but without majorly pivoting your core value proposition to the persona.
That way, later on when you need to zoom out (take your thumb off the hose), you can remove those segment filters but not have to pivot off of your core persona that sat underneath them.
As for other axes of segmentation, it varies a lot by your business model. One that I like a lot (and that people use Crossbeam to discover) is what other tech tools they are already using. It can really tell you a lot about their tech sophistication, ability to pay, and organizational maturity.