[andrewcooke]

they do similar things, but have different funding models. since ghostery makes money from selling stats to advertisers you need to be a bit more careful when configuring it if you want complete privacy (disable reporting and enable automatic selection of new updates).

there was a bit of a bitch fight between the developers here a few days ago - i couldn't find it on google, but if you can then it gives some context.

personally, i install both. they seem to run fine together.