Why? Mostly the usability sucks.
- Navigation is not very easy -- the navigation has gotten easier, but it still doesn't work very well with a traditional keyboard and mouse. I can't imagine trying to use it on a mobile device. I expect to be able to move my mouse and my avatar will follow -- in as much as I can see, that doesn't happen. The mouse is more an extension of your hand, in that anything that you click on, interacts with you in whatever way that it can. Your avatar will not walk over to the object first.
- Directions / help are terrible, if available at all.
- Design is hard -- Although I can find my "closet" aka in second life terminology, inventory, I haven't found an easy way to see what the clothes look like before I put them on. I've also found a couple of places where I can create/design artifacts via secondlife. End user / community generated content should be easier.
- Slow to load / high demand on computer resources -- Even on a decent enough computer setup for multimedia/video (albeit, not a gaming computer), some "lands" (think: villages or cities) are very slow to load. I think my avatar is getting bored waiting for the graphics. ;-)
- Other users -- well, there's another issue altogether. Given that I'm still learning my way around, I'm not spending a significant amount of time talking to others.
- The cost factor -- It's a little bit hard to find the free stuff in SL. Searching for free stuff is the best way (or join a "freebies" group), but for the most part, there are quite a few people attempting to make REAL money in SL.
(btw, this is NOT me)