Once you have your account set up, you know who you are and where you are, you might want to switch to another viewer. Just like in Internet browsers, there are different viewers for the same Second Life grid out there. You’ll find yourself in the same place, your inventory is still there, and you can safely switch between viewers for different uses if you like.
The single most used other viewer is the Firestorm Viewer, for a good reason. It is a brilliant all-rounder, and for most of us, it is all that we need. The main difference why most people switch to it from the Second Life viewer is the fact it supports RLV (restricted love viewer), which, in turn, enables BDSM games. That’s not the ONLY benefit of it, but it is, probably the first motivation for the switch.
The next most popular viewer is the Black Dragon viewer, that is much appreciated by people who do “Second Life photography.” To be honest, my knowledge of the Black Dragon is very basic, but there are people who swear by it.
CatzNip is another viewer that deserves mention, hailed for its speed optimization for those whose computer power needs a little lighter loads.
In addition, there are so-called subset viewers, that work from a browser or mobile. Out of them, I use SpeedLight when I’m not at my laptop, but perhaps taking a walk while having a chat with someone on Second Life. It works from a browser window, however. It gives you a basic 3D view of the world which is pretty impressive, albeit defaults your character to a very basic one. Others using a full viewer will see you normally, however. It also supports RLV which becomes handy when you’re using a mobile phone on Second Life.
Linden Labs (the creator of Second Life) is also developing a mobile viewer for Second Life and it’s looking pretty good but not, as of writing this, yet available.