Do you poll your class?

In your classes or workshops do you use polls to understand what your students are thinking? Have you considered using polls? If you have what methods have you used? There's many Audience Response Systems out there, but these are quite expensive.

I'm keen to understand your thoughts and past experiences on this type of classroom/seminar/workshop interaction.

I have just launched a SMS Poll (www.smspoll.net) that I believe would be of great benefit to Students (for their presentations) and for Teachers when interacting with the classroom. It's simple to use, you can sign up for free and the students use their own mobiles or laptops to vote. I have posted a forum discussion here. http://www.classroom20.com/xn/detail/649749:Topic:167664

I would love to hear your feedback on whether you think you would find this product useful and also if their are any features you feel could be added to improve the product for the education sector.

Cheers,
Ian