So the basic gist is, Anarchy Online (AO) is your standard massively multiplayer online RPG. (MMORPG :P) It's scifi, so instead of "Spells", it has "Nanos", as in nanoprograms which do things with nanobots.
All (well, most) of the nanos in AO are organized into lines. You start with, say, Limited Grid Jump and proceed along Grid Surfer to Gridspace Freedom. That's the Fixer runspeed nano line - well, there's a lot more in between those, but that's not really important right now ;) Obviously as you proceed along the line, the requirements get higher, as do the benefits. Within a line, nanos don't stack - a better nano will replace the worse one. Outside line boundaries nanos will almost always stack, even if they do the same thing, though there are some occasional annoying exceptions.
The obvious question is, "Where do you get nanos?" And that's what a lot of this hinges on.
A lot of nanos can be found in shops. There's one shop for level 1-50 nanos, another for level 50-90 nanos, and another for level 90-125 nanos.
You can't buy any nano past level 125. You have to find them out in the wild. The situation is even worse for neutrals, who don't get 90-125 shops (though they're apparently adding them for us in the expansion pack). We don't get *anything* past 90 easily, though sometimes we can buy them from an omni or clan friend.
So the obvious question is, how do you find them? Well, most nanos that you could, in theory, find in the shop if the shop went high enough you can also find as mission rewards. See, you can go and request a set of missions, and it shows you what you'd get for completing the mission. And if it's not what you're looking for, you can try again. Sound boring? It is. Luckily, there's a program that can do it for you, at one set of five missions per two seconds (server-imposed limit) so it's not nearly as bad as it could be.
There are some nanos that can't be found in shops at all, though. If you're lucky, they can be found as mission rewards. For example, Distracting Sphere or its big cousin Summoning of Balbuto the Gibberer are both missionable, though they can't be bought in stores.
Well . . . some can't be missioned for, either. For example, the ever-elusive Grid Armor, one of the rarest nanos in the game. For these, you go out and kill things. And pray.
In a way, it gets worse. See, some items will only show up on bosses of team missions. Meaning you have to get a team mission, and beat it, in order to get the item. And be lucky. Oh, and get it from whoever looted the corpse - with any luck, they'll be nice and give it to you :P Relieving Salve through Hacked Diagnosis can be bought in shops, but Kitchen-Sink Surgery all the way through Dr Hack 'n Quack can only be found as team boss loot.
The only way it isn't actually worse is that I don't know of any team-boss-loot nanos that are as rare as Grid Armor and Nullity Sphere is. In fact, I've gotten about five Kitchen-Sink Surgeries so far - obviously I only need one :P
The only thing that's worth mentioning in making things even *harder* is that sometimes you don't get a nano crystal, you just get an instruction disc. An instruction disc is basically the raw data for a nano, and you need to do a lot of work to turn it into a usable nanocrystal. Unfortunately, Grid Armor is only available in disc form, and so you *have* to find a trustable friend (usually) in order to actually *use* it. Grid Armor's not the only one, but most things are available in crystal form.
If anyone wants to look through a class's nanos in high detail, here's a fantastic Fixer guide, listing every nano we have and including the requirements and all.
And that's all. ^^