In fact, I used to be fairly active in the Active Worlds community, under the name "Vork" and could provide a bit more info. Lights, please.
Active Worlds
First, you must go to the website, http://www.activeworlds.com and download the browser, which is entirely free of charge. The browser is broken into a few sections. At the leftmost side is a little tool list, which has options to view all the available worlds, Send Telegrams (if you're a Citizen,)maintain a Contact List (seeing if your friends are on, and what part of the universe they're in,)and a list of Pre-set and User-Defined "teleports" to places you've visited and want to remember. It also contains an EXTREMELY helpful "Help" section, which covers almost everything you'll need to know about Building, the Browser, and everything about the AW universe. In the middle of the browser is the main viewscreen, which is a virtual-reality 3D display of the surrounding world (which can be set to first or third-person viewpoint, and zoomed and changed at will.) Below the main window is a chat window, displaying messages that you've said and have heard said nearby. And to the right is a miniature internet browser, to display webpages you encounter in AW. (which is fully capable of loading E2, by the way.) But basically, though, Active Worlds is one of those things, where you're either likely to love it or hate it right off the bat... although you can grow to like it or get tired of it as time goes on, like all other things. It's driven by VRML-derived technology, and it involves moving your "Avatar" through a fully 3d world. Motion is extremely free and fluid, and your Avatar can run, fly, and walk through any object with ease. (in most worlds... some worlds have restrictions on free motion.) Using simple keyboard and mouse commands, you can create new objects in these worlds... things like walls, doors, grass, trees, staircases, rocks, plants, furniture, in a wide variety of tastes and styles, varying from world to world. The idea is to create your own beautiful spaces with these objects, for all to see. Use your imagination. It's a LOT like building with Lego Blocks was, when you were a kid. The interface takes a bit of getting used to, but after you've gotten it down for a while, it's easy and fun. Using its object-oriented programming, you can even create opening doors, mobile objects, flashy displays, or even import pictures, textures, models, music, or Webpages from the Internet into your object. This allows for a very dynamic and enjoyable experience.
Worlds
Active Worlds offers a wide variety of different worlds to build in and to tour. A handful of then are run by people from the Active Worlds company, but there are roughly 700 user-created worlds (in the main Active Worlds universe alone... a few independent, alternate universes do exist.) At any given point in time, around 100 Public worlds are occupied and active, and 400 users are online. Numbers may vary, naturally, depending on peak times and all.
AlphaWorld
AlphaWorld (AW)is the original world of Active worlds, as the name suggests, and it's almost always the most popular one, boasting a population of around 100 users at any given time. A map of AW can actually be found online, at http://mapper.activeworlds.com/aw which will apparently be updated again in August 2001, if everything goes according to planned. AW is monstrous, and there's tons of room left for building, so it's a great place to start out and experiment with. An Object Yard is also available, which is a collection of every single oject available for building in the world (The method by which you build is a little strange. You clone an already existing object, then you edit its properties and change its filename to the filename of the object you want it to be. It sounds complicated, but it's pretty simple once you get used to it, and a little scratch pad is VERY reccommended if you want to do any serious building, so you can write down names of objects that you like. The main AW Object Yard is located at 1095 N 988 W in AW.
Other Worlds
There are a few
other worlds worthy of mentioning, although none of them near
AW's popularity, they do offer a wider variety of places to travel and build in. There's
Atlantis which has a sort of underwater motif, and
Colony Alpha which is a more futuristic flavor of regular
AlphaWorld, based on a sort of colony on another planet. Then there's the dark and futuristic city of
Metatropolis, with a few
terminals that you can jack into and explore a strange and twisted
computer world of sorts.
Mars is also a choice, with futuristic building on the
Red Planet, and dust and
spacecraft.
International Worlds all abound, filled with people from all sorts of different countries around the world, and themed likewise.
Simple Geometry is one of my personal favorites... in this world, the only objects available for building are
cubes,
pyramids,
spheres,
cylinders, flat
planes, etc.. It's a lot like playing with a
child's building blocks, and some pretty impressive
structures are in place there.
AW Community Center is the big event
center of the Universe, where
scavenger hunts and festivals are announced and planned out, and it's quite a
nice looking world at that. A somewhat
thriving community still exists on AW, though its
popularity seems to have declined a bit over the past few years, it's still
going very strong. Various other worlds exist as well... go explore, find them for yourself!
Citizenship
As time went on, and AW grew larger and larger, it naturally became quite expensive to maintain this giant project... and it required money to continue. The answer was Citizenship. this means that ANYONE can log in to Active Worlds as a "Tourist" and can explore all the worlds, move freely, chat freely, and build freely. Being a Tourist is totally free, and isn't such a bad deal at all, as you get the general idea of what the experience is all about. However, as a Tourist, the big, big, big disadvantage is that your property is NOT protected from deletion. Any object that you place can be deleted by any bozo that happens to wander by and decides to delete some poor tourist's porperty. Even a Tourist can delete another Tourist's property... so you can't do a lot of serious bulding as a tourist, or you can only really do it in a very remote location. Additionally, you cannot send "Telegrams" as a Tourist, and you are limited to the choice of one Avatar, the "Tourist" Avatar. With a Citizen account, you get your own Citizen name, your property cannot be deleted by anyone except for you and the Administration, and you get full acces to the Contact List, Telegrams, and the full Avatar Selection. The cost of Citizenship is $20 US for a year's worth of Citizen access... whether this is a good or bad deal is entirely subjective, and depends on how much you like AW.
And that, in a nutshell, is the Active Worlds experience. Go ahead, try it out if you like, it's pretty fun to build stuff and talk to people. It's even more fun if you can work on stuff with a friend, I've found. And, as always, enjoy!