This question maybe a better fit on The Business of Software forum but despite my post on there, I'm still unable to determine the following: Can I use the Google API to build commercial software? If not how can the people behind Byline charge for their app?
Update: I'm specifically interested in Google's Picasa & Reader APIs
From the Google Terms of Service:
5.3 You agree not to access (or attempt to access) any of the Services by any means other than through the interface that is provided by Google, unless you have been specifically allowed to do so in a separate agreement with Google. You specifically agree not to access (or attempt to access) any of the Services through any automated means (including use of scripts or web crawlers) and shall ensure that you comply with the instructions set out in any robots.txt file present on the Services.
(emphasis added)
More specifically, when you say "the Google API", which of the many APIs Google exposes are you referring to? Each of them has different terms of use. Some can be used commercially, some can't.
Update:
from the terms for the Picasa Button and Uploader APIs
7.1 Subject to the Terms, you may develop, display and/or distribute your Button using the Services as part of a commercial or non-commercial enterprise, and you may develop your Button for use in accessing paid content or services. You may not charge a separate fee for use of any Button, unless you have entered into a separate signed agreement with Google. If you wish to sell or transfer your Button, you must obtain Google’s prior written permission.
from the terms for the Picasa Web Albums Data API
5.8 You may use the Picasa Web Albums API as part of a commercial or non-commercial enterprise, subject to these Terms. You may not however charge a separate fee for use of the Picasa Web Albums API unless you have entered into a separate signed agreement with Google.
As far as the Google Reader API is concerned, it still appears to be unreleased and so no specific terms are available.
To enter into a signed agreement with Google, you're probably best off contacting your local Google office and talking to one of their business development representatives there... Alternatively, you could try contacting the Business Proposals department from their contact page...