We'll have to treat it as a smartbot and exclude the preview as a visit. There's no referrer information, the IP belongs to Google's netblock, and the user agent looks like Safari 3.1.

If the IP belongs to google netblock, does it mean it is currently excluded from being tracked (as it should be, as it is a bot)?

(In [3310]) fixes #1809 - ignore visits via Google Instant Preview as it skews Safari visits, and doesn't provide any referrer information (i.e., keywords). Plus, it looks like the preview image may be cached by Google (and thus, a preview may not always result in a web page being fetched)

Note that GA also had the issue themselves:

http://analytics.blogspot.com/2010/11/instant-preview-issue-resolved.html