FREEMIUM is business models usually involve a Free service, sometimes time limited or feature limited, supported by advertising.The goal is to convert these free users to paid subscriptions.

FREEMIUM was first articulated by venture capitalist Fred Wilson on March 23, 2006. "Give your service away for free, possibly ad supported but maybe not, acquire a lot of customers very efficiently through word of mouth, referral networks, organic search marketing, etc, then offer premium priced value added services or an enhanced version of your service to your customer base."
http://en.wikipedia.org/wiki/Freemium_business_model


online businesses utilizing FREEMIUM are:

1/ MEETIC
2/ SKYPE


The advantages for FREEMIUM are :

1/ It allow customers to experience the products before paying it.
2/ il allow customers to have a general idea about different products without any fees.
3/ it allow customers to have their own idea without being influenced by communication or media


The disavantages are:

1/ customers can have an idea about the products before buying it, it could be bad for the company if customers didn't like the product.
2/ customers can use only the free part of products, for example, only using SKYPE for usual calls, witch is free.
3/ customers could give to product a good value before using it, and than to be less satisfacted after using it.