Facebook contest and vote(like) exchange

Question

UPDATED

we are running a contest using a facebook application to connect with facebook and identify users. a user follows through the standard facebook procedure to allow the application and login.

the user then can vote for any entry only once. the vote is saved to avoid the same user voting twice.

since the contest has a cash prize we face the problem of vote exchange. vote-exchange is the process where one individual goes to a group-page-forum-etc and trades his voting to another contest, for people voting for his entry in our contest. in essence "buying" votes. they achieve higher number through fake profiles (another problem)

so we are faced with:

1. how to detect this vote exchanging
2. how to detect fake facebook profiles
3. in general how to safeguard such a procedure (with or without facebook)

right now we are looking for the blindingly obvious violations

1. Very similar emails(john1@ , john2@)
2. Sudden spike in votes (in terms of timing and vote count)

Answer 1

You seem to have two main issues here:

1. There is not a 1-to-1 relationship between facebook accounts (id) and voting entities (people)
2. Voting entities are using their votes in ways that you do not expect.

Issue #1 is solved by various forms of limiting (See: StackExchange voting success). Basically, you should choose some criteria from facebook profiles that generally distinguish "fake" accounts from "real" accounts. There are a number of possibilities for this.

• Account creation date
• Number of friends
• Total account activity
• Amount of profile information available
• Participation in a invite-only group

You can mix and match any of these items. I'm sure this problem has been tackled before in many different spheres--you might be able to find existing heuristics made publicly available to solve this. This may be only a small obstacle for many spammers, but until Facebook implements a solution for this issue, it is probably good enough to try to filter on your own.

Issue #2 is more of a social problem. There is probably not a solution to this. If you allow the freedom of voting to every person, they will vote in any way they please, for any reason. This may just be a perception issue on your part. Depending on the problem you're trying to solve with this voting system, you may be able to use another solution.

Some alternatives which may apply:

1. Embrace the fact that people want to enlist friends to help. Have a Referral contest. Referral-based contests happen all the time, and work generally well.
2. Don't use votes--have the contest be single-entry, random victory--Where everyone gets an equal chance to win. If part of an entry is a unique piece of information (like an address or telephone number), there will be no duplicate entries. Alternatively, judge entries instead of using vote systems.

Of course, it's possible that neither of those could help, depending on your problem. Hopefully they can help you look in the right direction, though.

Answer 2

Trying to detect fake profiles etc. is an arms race that you're unlikely to win. As for things like vote-exchanging.. I actually would have thought that if you're running a Facebook competition, you'd be glad to have people soliciting for votes - isn't the idea of your competition to draw peoples' attention?

An approach that has worked well on a few competitions I have done the technical work on is: only have a relatively small prize for the entry with the most public votes; the real major prize is awarded accorded to a judge's decision. So people still have the fun and excitement of trying to get votes, but ultimately, if someone totally stacks it, it's no big deal.

One other thing: make sure you're not creating a snowball effect yourself. e.g. if you have lots of entries, and on the front page of your site you display the current highest-voted entries, a lot of people will only ever see those ones (and give them even more votes!), never click through to see others.