Originally Posted by jayeff

That's only a partial solution. Check out the sites in "tlist.dat" that this one guy is botting... there are several there big enough that their traffic gets everywhere.

I'm not enough of a coder to know whether this particular bot can go more than one level deep, but there are plenty around which can. Thanks to them, although you can avoid the worst effects by picking your trades carefully, you still end up trading bot traffic. You get it from honest trades and pass it on just as innocently.