Who knows, maybe the dictionary is wrong, but I guess it wouldn’t be wrong to extend the meaning of usyoso. Yay for language evolution

The way I’ve been using (and heard it being used) is more about the act. For example: “Nakiki-usyoso ka pa dyan! Pumasok ka na nga!” (“You’re even spectating over therel! Come right back in, you!”)

There’s another word, usisa, which I would characterize as more like “to investigate, to look into” but is also akin to usyoso in a way I just can’t put my finger on. I think it got conflated with usyoso as the colloquial uzi (from usisero/a, “someone who is overly-curious”) took hold (example: "Uy! Wag ka ngang uzi! Kita mo na ngang nag-aamok na yang si Mang Torio eh. Pumasok ka na dito, bago ka pa madamay dyan!" [“Hey! Stop being an onlooker! You already see Mang Torio running amok. Come back inside before you get involved.”])

I’d use neither to refer to the feeling of “wanting to find out about someone I’m spectating on” though. Personally, I’d just use something like na-intriga (“got intrigued/curious”). For example: “Na-intriga ako dun sa nabasa kong blog kagabi. Ano na kayang nangyari sa kanya. Huling post nya 2020 pa, tapos depressing pa yung post.” (“I’m curious about the blog I read last night. I wonder what happened to them. Their last post was on 2020, and the post itself was depressing.”)