FormTextResizer is a bookmarklet that allows you to resize any textarea or text input on any webpage. This way, you won't be confined to a teensy little comment box or e-mail field. Just activate the bookmarklet, then click-drag on the textarea or text field that you want to resize. Simple!
Right-click here and "Bookmark" FormTextResizer to access it anywhere, or click the link to try it out.
Note: Internet Explorer places a restriction upon bookmark URL lengths, so use this Internet Explorer bookmarklet, which links to a script on my server.