Scammers have begun abusing Facebook's Chat feature to trick users into participating in rogue surveys by promising them free iPhone 4 smartphones in return.

Scams in which users are lured onto rogue pages and asked to complete surveys in exchange for access to some intriguing video or picture have become a common occurrence on Facebook in recent months.

Compared to other traditional forms of spam delivered via IM or email, where the spammer needs to invest significant resources in order to reach a large audience, Facebook scams have a significant advantage – they rely on users for propagation.

However, even though not as convenient, Facebook chat spam can also prove very effective in tricking users, especially since people are starting to catch on all the wall spam campaigns.

The newest scam to abuse Facebook's chat feature is promising free last generation iPhones to people who go on a website and provide personal information about themselves.

"Hey [name] I just got my free iphone 4 in the mail and thought you might want it too so go here http://bit.ly/[censored] and put in your e-mail and shipping stuff and they will send you it. thank me later :)," one spam message sent via Facebook's Chat reads.

The link leads to a site that has nothing to do with iPhones and is offering payment in exchange for completing online surveys. This is probably not true, or if it is, there's likely more paying involved than winning.

For one, it requires an account and the registration process asks for a wealth of personal information, that will almost certainly be used to fill your email inbox will targeted advertisements later.

We've seen the free iPhone or free iPad lure used before in scams on both Facebook and Twitter. In such cases it's good to keep in mind the old saying: "If it sounds too good to be true, it probably is."