I'm just looking for people's opinions on this...
I really got worried when Second Life came out; I thought it was going to be a game changer for the Internet; Until I realized that outside of programmers and college students there really aren't that many people with the sort of hardware and Internet connection requirements needed to have a decent user experience with Second Life.
That compounded with the fact that a Linden Labs server can really only handle about 70 people visiting a land at one time. Thus whatever interactive 3D content you create on Second Life cannot possibly generate the number of hits that you might get with a traditional web app.
But even so, for the future...when maybe they find a solution to this problem, is it worth learning LSL?
As usual with such questions, it depends on your goals.
Reasons to learn LSL:
Reasons not to learn LSL:
I have nothing against LL or SL, and might dabble with LSL for fun if I had nothing else to do. But I already have lots of other things to do.