or, to add a third option:
"Available online only"

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Note added at 16 mins (2012-09-13 16:19:51 GMT)
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"First Direct Checking (available online only)"

http://www.firstcloverleafbank.com/home/personal/personal/fi...

"To order a copy of this publication, select quantity and "add to cart".
Only available online"

http://ndep.nih.gov/publications/PublicationDetail.aspx?PubI...

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Note added at 20 mins (2012-09-13 16:23:56 GMT)
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While Google is not the be all and end all, it is useful for comparison:

"available online only" 15,400,000 hits
"only available online" 1,490,000 hits
"available only online" 146,000 hits