I will discuss 1) client side hacks, 2) protocol hacks, 3) cheats and 4) automation tooling.

1. client side hacks

On YouTube you will find a gazillion movies about "hacking FarmVille" with all kind of nice titles and demonstrations. What they achieve however is just changing bits in the client side application and not in the server-side application. If you are computer illiterate you can view this as:

you fertilize some land and an update gets send to the FV_achiement.SWF file on the server.

The so called hack tools change values only in your client application (so on the right), which means: yes, you are the owner of your own PC, you change what you see to anything you like e.g. make the XP numbers go to a gazillion. However… when you reload the application (so that it gets transfered again from the server) your client application will again hold the initial values.

So there is no real hacking here only client-side fun, you could just as well turn off and on your screen and say that you made FarmVille go on and off for millions of players on facebook.farmville.static.zynga.com.

It doesn't mean that this method will never work. Not so smart programmers might actually rely on client-side operations to update values on the server. The Zynga developers however rely on communication between your client and the servers in which they handle the security around cheating.

Unfortunately thousands of players are looking for "hacks for FarmVille" and lots of sites have been setup that deploy viruses instantly in your machine (or try to). There are other sites I have seen that try to lure you into signing up first with all kind of dubious sites before you get "the cheat". Well.. hopefully you are smart enough not to fall for this.

Once in a while some hacks are found e.g. by manipulating the gameSettings.xml, by performing certain actions that do have a permanent result, however the Zynga developer mostly fix these ones quickly.

I will quote the code of conduct:

Posting Cheats, Hacks, Trojan Horses, or Malicious Programs
Posts and/or private messages that allude to, contain language, comments, references, links, symbols, terms and/or imagery about and/or promote and/or otherwise support, in any manner whether directly or indirectly, cheats, hacks, cracks and/or malicious viruses/programs (e.g., keyloggers, Trojan horses, websites or files that take control of another person’s computer, etc.).

and the TOC:

xi) copy or adapt the Service’s software including but not limited to Flash, PHP, HTML, JavaScript or other code;

and:

xii) reverse engineer, decompile, reverse assemble, modify or attempt to discover any software (source code or object code) that the Service create to generate web pages or any software or other products or processes accessible through the Service;

2. protocol hacks

Almost everyone who is a bit "techy" has Firebug installed, so to see (of any website) what goes over the line is basic practice (it is even build in in Google Chrome and tools like Fiddler show even more). So what people try here is to analyze this communication and they try to "tweak it".

As far as I have followed the updates this has not been done yet successfully and even if it has, I hope it is a security specialist who then first contacts the Zynga developers to correct the problem first. update: see the comment beneath on debugging the flash protocol.

I will again quote the code of conduct:

Posting Unreleased Content / Hacking Data Files
Posts and/or private messages that contain language, comments, references, links, symbols, terms and/or content that, in any manner whether directly or indirectly, show/display and/or discuss any of the following: (a) unreleased in-game items or equipment; (b) areas that have been unlocked by hacking into client data files; and/or (c) data not available through normal game play.

And the TOC:

xii) reverse engineer, decompile, reverse assemble, modify or attempt to discover any software (source code or object code) that the Service create to generate web pages or any software or other products or processes accessible through the Service;

and

xvii) interfere with or circumvent any security feature of the Service or any feature that restricts or enforces limitations on use of or access to the Service, Collaborative Content or the User Content;

3. cheats

Cheats are basically bugs that are exploited. When you are a developer and have to develop a software program you can not think of all possible situations that arise, especially in a hectic environment. So bugs arise. In general it is believed that any 1000 lines of of software code contains about 20 to 30 bugs. (including your operating system) (and hardware drivers contain a much higher percentage).

Now, just as you read in the newspapers everyday there are people out there looking for these bugs and looking for ways to misuse them. Within this game the same happens. Let's say that FarmVille contains 10.000 lines of code, this means that there are at any time 200 bugs.

So, in general, people finding the bug for the first time (e.g. the endless gifted cow) have three choices:

1) either they mail them silently to the development team (I could not find a link however),

2) they post them publicly in the message board (here) or …

3) they post them on their weblogs and let the whole world know that a bug exists which can be exploited, which is a bad thing.

So shortly said: yes bugs and therefore exploits do exist, yet I hope (since its just a game) most people will silently message the development team (though I could not find a link yet).

The reference to the TOC:

xix) engage in cheating or any other activity deemed by Zynga to be in conflict with the spirit or intent of the Service.

4. automation tools

This particularly game invites for automation of tasks. There are numerous tasks players have to click, click and click :) :

• daily harvesting / collecting
• daily getting of gifts / neighbors
• daily visiting neighbors / fertilizing

And I'm not talking even about soya conversion.

So it is no wonder that on almost very automation tool forum there are threads about FarmVille automation.

I don't know if it is exactly cheating it is basically "automation of repetitive clicking tasks", see e.g. some greasemonkey scripts or this thread on auto-it. It is a very thin line here. I mean, greasemonkey scripts are what we use on any other site to make our lives handier e.g. automating some tasks in gmail. It feel therefore I think for many users very unnatural nowadays to not try to make your life somewhat easier.

Basically it is not much use of doing these things other than help yourself. You will not harm anyone else, you do not hack into something that you should be into and after some automation I guess that most users will just focus on having a nice farm instead (what else is the point). Basically it is a choice of the user himself and it is furthermore highly undetectable if someone uses automation or not (someone could actually be clicking on the other end).

It does mean however that you have the chance that you get banned from the Zynga games if you use it extensively.

from the TOC:

xiv) except as may be the result of standard search engine or Internet browser usage, use or launch, develop or distribute any automated system, including, without limitation, any spider, robot (or "bot"), cheat utility, scraper or offline reader that accesses the Service, or use or launch any unauthorized script or other software;