In Safari on the iPhone, the toolbar is the bar across the bottom that has the forward, back, share, bookmarks and tabs button. In iOS 7, they’ve changed the behavior so that the bar automatically hides itself as you scroll down the page.
To get it to reappear, you either have to scroll up a bit, or tap near the bottom of the screen. Or so I thought until I discovered that you can swipe forward and back between pages *without* using the toolbar!
To do it, just swipe from the very edge of the phone itself (I usually start by touching the black area between the left/right edge of the screen and the antenna band) and then swipe across. Voila! Now you can go forward and back in Safari using gestures!
(This trick also works on the iPad!)