I'm not talking about the book of the same name, which may be very good but I've never read it. I'm referring to what is possibly my favourite website and certainly the one on which I spend most of my time - www.makeupalley.com.
I've been using this site for years - it must contain several thousand reviews of beauty products including cosmetics, toiletries, hair styling tools, make up brushes and fragrances. It also has several very active message boards which I've only recently discovered - throw out a random question (it doesn't have to be beauty-related - there are numerous others including fashion boards, fitness boards and ones for general chit chat) and you'll usually have several responses in just a few minutes (my latest was to ask what make up would complement a royal blue dress - a bronze eye seemed to be the consensus!).
On first impressions makeupalley may look a bit dated and amateurish, but for me that's part of its charm. Its primary purpose is to be a beauty resource and all of the information is easy to access without distractions from fancy graphics etc.
As well as doing basic searches you can narrow your search down by the age of the reviewer, for example, a woman in her 30s would probably be more interested to hear what someone a similar age thinks of a face cream than say a girl in her teens or twenties. You can also search my most popular products, most reviewed and newest products listed, and you can add new products and brands if they're not there.
I think makeupalley (terrible name I admit but even so I'm quite fond of it now!) is the trip advisor of the cosmetics world. It's a fantastically useful resource - I've bought so many amazing cosmetics following recommendations on makeupalley. The uninitiated (poor souls!) may think its a bit over the top to research a beauty item online before buying, but considering the cost of some items nowadays, I actually think its very prudent.
Long may it continue!