Users use forms to do many things. Finding a local store to shop at is one thing that should take them little time and effort to do. However, most store locator forms are hard to use and take up too much time.
When designers think about forms, they usually think about text fields and submit buttons. Checkboxes often get ignored because they aren't used as often.
Anyone who has a form on their website has seen their fair share of spam. Spam is a huge problem for site owners. It can cost businesses time and money. To fight spam, many sites put captchas on their forms.
Are you thinking about using modal windows on your interface? Modal windows prompt users to choose an action to take before they can return to the main window.
Users used to see popup windows everywhere on the web. Today, modal windows have taken its place. With modal windows dominating the web, popup windows are now a thing of the past.