One kind of orb-weaver that does not make vertical webs is the long-jawed orb-weaver. This spider often makes its web across the surfaces of our ponds, usually at an almost horizontal plane. Most of the other spiders we have make vertically oriented webs. Spiders rebuild their webs quite often, sometimes every night, eating the old web before creating a new one.
A predominate species of orb-weaver is the argiope. This fascinating spider grows quite large and often stays in the same location all summer. When argiopes are small, they create a wide central area of bright white silk. As they mature, this area becomes a long central stripe. I've never heard a positively proven reason for this white patch (which other spiders also make), but it probably has something to do with either camouflage for the benefit of predators and/or prey, or may even lure insects as the silk reflects ultraviolet light like flowers.