A touchy subject with developers, blocking ads on your handset offers the user a more pleasant experience at a dollar cost to the developer that created the app.
Personally, I prefer my apps to be ad-free, but don’t mind paying the few dollars to upgrade an app to an ad-free version. I think all developers should offer this option, but many don’t. In those cases, it’s pretty easy to forcefully remove those pesky ads.
There are apps out there can selectively block ads (for example, Ad Blocker & Data Toggle is $1.99 on Google Play), so you can leave ads to appear in those apps whose developers you’d like to support. While it’s great that this particular app doesn’t require root access, the app isn’t 100% reliable.
So for those hands-on Android users out there (those who laugh in the face of warranty claims), there are system-wide, root-only methods.
Like almost all operating systems, Android has a hosts file, which maps names to IP addresses and can be fiddled with to prevent certain servers from being contactable. This gives a user two options: open up a command line and 'adb' your way to ad-free browsing, or more simply, just install an app.
If you’re an 'adb' guru or an old hat at editing hosts files, you can find your host file at /system/etc/hosts. However, I don’t really see any advantage to such command line shenanigans when there are perfectly decent (and transparent) apps to choose from on Google Play. My favourite such app is AdAway because it’s open source and it regularly updates the hosts file, making sure your phone is as ad-free as possible.
After installing AdAway, modifying your hosts file is just a matter of hitting the big ‘Download files and apply ad blocking’ button. The app will then run off to four different sources for hosts files and compile an uber hosts file, which will all but guarantee an ad-free experience on your phone.
Note that if you’re a Words With Friends player, your phone won’t load properly after you reboot, as the game runs at startup, and stuffs something up if it can’t reach its server. This freaked me out more than a little, as my phone wouldn’t load its launcher after I rebooted.
Thankfully, the app offers white and black listing of servers for just such a situation. You should check the AdAway problem apps page for the latest app list, but as it stands, Words With Friends requires androidsdk.ads and mydas.mobi to be added to the white list, while WordPress Stats requires stats.wordpress.com. If you use either of these apps, make sure you add these servers to the white list before you apply the ad blocking.
Now the only thing that may get in the way of an ad-free experience on your handset are those apps that deliberately look for and disable ad blockers, but I guess you can’t really get upset at a developer for wanting their just rewards.