The fact of life is that for the majority of visitors, what describes your site is its name. And that's if you're lucky: on Computer Science, we get quite a few “fix my Windows” questions, from people who stopped reading at the first word. (And then there are the desperate “hey, a text box” cases, who ask about gardening or relationship advice on Stack OverflowStack Overflow.) The better ones will also read that introductory sentence (“is a question and answer site for people looking to bypass life's everyday problems with simple tricks”) and at least part of the tour page.