This situation reminds me of Microsoft buying a small portion of Facebook at a large valuation. In that situation, it was more about the relationship such a deal would create rather than the actual numbers behind it. By creating a large valuation with a small deal, everyone wins. The investor doesn't have to put a large amount behind it while the startup gets the glory of an impactful validation.

http://www.nytimes.com/2007/10/25/technology/25facebook.html...