Uses of computing power by bitcoin miners How much of what this article says is true?  I thought I had read that bitcoin miners are the ones who maintain the blockchain.  Do they also do something other than maintaining the blockchain?  In particular, things that no one would otherwise want done?

http://gizmodo.com/the-worlds-most-powerful-computer-network-is-being-was-504503726
YES.
1)They help maintain the reputation of bitcoin by showing how it "works" and demonstrating that you can make money AND THEREFORE
2)They help encourage the developement of more powerful mining rigs and the business sector that makes them AND
3)They encourage more mining activity AND
4)They increase the difficulty.

GO TO 2).

Oh, just forgot one..

5)They help keep the planet nice and warm with all the electricity converted to heat by the mining rigs (I do hate being cold !).

6)AND ALSO (see my previously posted question): The may(or may not) be effectively working for the NSA (or someone) by helping to crack and/or obtain hash results of SHA256 which may (or may not) be useful (for someone to do something) such as constructing a larger look up table for SHA256 (e.g. crack longer length passwords.).

I suppose if you own a nice big mining rig (or otherwise have "control" of someone else's) it might be more cost effective to use it to hack into something rather than mine coins so I think one answer to the question would be "Yes, but not bitcoin mining if you choose to use the rig for something else more profitable and are dishonest/criminally minded".