Its a fun book, and a good intro to Stephenson (it was my first book I read of his, and now I've read four others). But if you've read his other stuff first or are a more hardcore sci-fi nerd, its easy to think that its a little closer to a blockbuster thriller than science fiction.
Its very different from Stephenson's other novels. Its much more of a thriller with a few tech elements thrown in. I really enjoyed it, but don't go in expecting another cryptonomicon.
Reamde, is a fast paced techno thriller. It's arguably one of his lesser novels but still a ton of fun IMHO.
The premise of the book is that of an online game that is essentially similar to world of warcraft with the difference that the entire point of the game is the in game economy.
This part of the book is pretty well developed and ties in nicely with his other novels that also deal with money, gold, crypto currencies, etc. The crisis in the game is when a group of enterprising chinese hackers deploy a virus that encrypts people's laptops via a bit of ransomware distributed via email. To unlock their computers people are to pay some of the in game gold in a particular area. All goes sideways through a set of rather unlikely coincidences.
There are a lot of other elements being dragged into this including a fair bit of gun wielding by terrorists, russian mafia, and the protagonist and his somewhat libertarian family. This is is not the most innovative plot and it is ultimately a relatively one dimensional plot that is in places a bit cringeworthy.
I still enjoyed this book and have read it multiple times. It's got plenty of side plots, detailed musings, and so on that are typical for Neal Stephenson. If you enjoy that kind of thing, this book is fine but it's no Anathem or Snow Crash.
It's been on my reading list for a while but the mixed reviews always lead to it being left for another day