Threadless, the T-shirt e-commerce site and community of artists who design them, is looking at the storefront option as well.

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The difference, says Idealab Chair Bill Gross, is that eWallet doesn't depend on mutual e-commerce pacts among Web merchants to work.

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Hard numbers are hard to come by because the company doesn't break out its e-commerce business, but the site is in the top ten in terms of visitors to e-tail sites, and its catalog is always expanding.

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