There are the differences in "white boards" and "smart boards" (which are white in color boards) that most educators do not grasp. SmartBoard, which like Xerox and Post-It, has become genericided, so we use terms like 'interactive whiteboards', 'whiteboards' and 'smart boards' interchangeably - thus leading to more confusion when these words are thrown around. A large touchpad with a projected image of a computer's desktop a nice toy, but, when we talk about whether they improve teaching and learning, we should consider how they are used.
Interactive whiteboards are stationary (not many teachers will not move it or allow it to be moved) and expensive. In a typical classroom, they are a tool (or crutch) for teacher-centered education. The teacher stands in front of the room, talks to students, and shows a PowerPoint or a web site. But, instead of moving back and forth to the computer to advance a slide to click a link, they tap the board. They can invite students to come up to the board to touch it, too. The teacher has the control, and educators view this teacher as using technology to teach. We have returned to 1801 when slate blackboards (new tech at the time) revolutionized education.
Single-touch iwb's are consider the boons of educational technology - every school I visit, every edtech grant I read, every conference I go to, educators wants to put one in every classroom @ $3000-8000 a pop. The understanding is that by simply putting this in the room they increase student learning and improve test scores. At that price, as a stakeholder providing the funds to purchase that board (tax dollars), I should expect that board to used every minute of everyday.
In 5 years, I have seen 2 teachers use SmartBoards effectively (1 Kindergarten, 1 high school) and 1 teacher who I thought should have one based on his use of a projector on a (non-interactive) white board. They used technology to support engaging, student-centered, and creative approaches in math and science. Good teachers use good technology effectively; unfortunately, they are rarely consulted as to what good technology is needed in the school.