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TA: How about a question mark just to the left of the close box, with the results of the click populating the overlay frame (rather than taking users to another full page, or pop-up)
PT: I like Trent's suggestion of a small question mark just to the left of the close box
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TA: There is some value to letting you know what you signed in with last time, but the little icon isn't enough. At the least some kind of confirmation "you signed in with Google last time, sign in again"
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TA: I would stop short of promoting the favicon in the bar. If you ask people show people a print-out of this page and ask "if you click this, what do you think this will do?" you'd get different answers.
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