Description

Requirements:

Android 2.3.3+
ROOT
Xposed Framework

This app blocks host names you don't like.

You could import "hosts"-files by given urls.
With this app you have no more to alter the /etc/hosts file on the system partition, which was also a problem on some devices (eg Nexus 7) because changes where reverted after reboot.

Technical:
Name resolution request are answered with "No address associated with the hostname". This is even better than a common hosts file with redirects to 127.0.0.1, because no connection attemp follows. For logging of hostnames is no tcpdump needed!

Browser:
If you want to block content of websites, you have to use a browser app which does not tunnels everything through a proxy! This is because the proxy does also the name resolution. Negative examples I found: Google Chrome, Mozilla Firefox or Opera Browser does not work.
I'm using Dolphin Jetpack, which works fine for me. Some more info in post #47 of the XDA thread.

Permissions:
RECEIVE_BOOT_COMPLETED: set timer for download
ACCESS_NETWORK_STATE: download only via W-Lan
INTERNET: downloading of files
WAKE_LOCK: don't sleep while dl/import
EXTERNAL_STORAGE: export/import files

Limitation:
No support of native querying binaries.