That article specifically refers to the original Win98 only, though I don't think the specs changed too much with SE. (MS doesn't seem to want to differentiate between the two.)
To run a USEFUL system with Win98SE, at least 32MB would be good, 64 even better. Though Win9x's memory management isn't as good as NT, it can still benefit from increasing memory that much, and even 128 can give a good boost. Beyond that isn't extremely useful, but if you have memory lying about, it doesn't hurt. (Up to 512MB. Beyond that you have to do some tweaking to make it work properly.)