Everyone"s an expert is the third installment on how to build a website that people go to by Seth Godin. I"m paraphrasing a bit.
Seth talks about how people don"t search for things to buy online. People search to make sense of things and take action based on what makes sense for them to do so.
High traffic blogs receive a lot of traffic for a specific reason. The reader trusts the author as a reliable source. One of the key factors is that a real person is in charge of the website and not a faceless corporation. People want opinions more than we might think. Your view point matters. The more specific you are the more expert you become in your field.
Build a lens. A lens is a point of view of what the reader needs to know now. A lens is also personal. It"s more timely than the blog post. If I understand correctly a lens can be a collection from your point of view. What you just read, your wish list, your Flickr photos and so on. This website is now my lens.
I think another application of adding a lens is by placing a context on your website that"s easily seen or noticed like on the sidebar. So the viewer will know in one or two sentences who you are and what your website is about.
There are many ways to build a lens. Seth recommends squidoo. I also noticed Leo Babauta of ZenHabits has a tumblr account as his lens. What is your lens?