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During the pilot, a service's particular error or alternate login page will have an additional button called "Try authenticating via Touchstone". So for example, if you try to log in to Stellar and your certificate does not work or you do not have one, you currently get the page below. 
When the Touchstone pilot goes live, there will be an additional section underneath the current MIT Community Users section on the page below.
During the initial phase of the pilot the pilot applications will always require an explicit customer action to "try Touchstone" if login fails by default. It should never re-direct there automatically, unless the user has at least once chosen to use Touchstone and set explicit preferences for their use of Touchstone.
Here is a screen shot of what a user of Stellar will see if a certificate is not presented to Stellar when logging in:
The login page for http://wiki.mit.edu
is intending to take a similar, yet slightly different approach as seen here: 
2) There are some "start-up" or transition aspects to using this service. It may slow people down, or require them to get some additional information before they can get to web-based information on which they depend to do their work or studies, and which is time-senstive. What can we say to someone about the benefits of this new system, which helps to offset the unfamiliar way of going about old tasks? We would expect clients to ask the following questions. What answers might we give?
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