He bid $500 at 5.54% on Andrew's loan; why isn't he throwing in at least a token $50 on Islandmele's? After all she's done and continues to do for Prosper, it seems like it would be a nice gesture.
Hi Caladia,
Normally, I count on you to be common-sense/voice-of-reason-y, but, I don't really understand why the above is your ("our") concern?
As TJ begins to point out, there are a number of possible explanations - but I'd point out simply that it's none of our business or money.
(I wanted to just post: "What are you, his mom?" - but wasn't sure it'd be taken quite the right way without a little bit of explanation.)

-t
Actually, it is our business. JWitchel's bids are not only symbolic of his confidence/support for Prosper.com itself, but also of his willingness to support those who support Prosper.com.
If this is the lense through which you wish to view his bidding activity, you're free to do so. However, it's a lense of your own creation.
Not putting even just a token bid on a loan for a person that has done so much to support Prosper.com is a bad PR move since it can be interpreted as a lack of gratitude.
If no bid is placed, someone who thought that it was "their" business would complain about how he's being "ungrateful" to the borrower.
If a "token" bid were placed, someone who thought that it was "their" business would complain about the bid being merely a "token" bid.
If a "non-token" bid were placed, someone who thought that it was "their" business would complain about the bid being "compensation".
(Then, of course, there would be a class-warfare side-fight between the camps who disagree about what constitutes a "token" amount.)
Who needs to argue about it? As you say, it's a matter of interpretation. The polite thing to do is keep your interpretation to yourself.
-t