No, they're not venomous at all actually.
They are venomous... just not considered lethal.
Banana Spider
Banana Spider A very large common spider in North America. Usually hangs in webs with its head facing the ground. It is brightly colored. Its venom is a neurotoxin similar to that of the black widow. However, its venom is not near as potent. Its bite causes local pain and redness with blisters forming. This bite usually resolves within 24 hours except for the bite mark.
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Nephila and humans
The venom of the golden silk orb-weaver is potent, but not lethal to humans. Its venom is a neurotoxin similar to that of the black widow spider; however, its venom is not nearly as powerful. Its bite causes local pain, redness, and blisters, but these symptoms usually disappear within a day (though the bite mark may leave a scar).[citation needed]
There were efforts to produce garments from Nephila silk. The spiders were fastened and the extruding thread coiled up until the spider was exhausted. However, this method did not prove commercially viable.[5] Fishermen on coasts of the indopacific ocean remove Nephila webs and form them into a ball, which is thrown into the water. There it unfolds and is used to catch bait fish.[5]
Nine golden orb-weavers from Australia perished in the Space Shuttle Columbia disaster. The "AstroSpider" experiment is part of an international program (STARS) that encourages students to design experiments for flight on the US Space Shuttle or International Space Station.
From
http://en.wikipedia.org/wiki/Golden_silk_orb-weaver