Has anyone else been the recipient of unexpected subcent transactions? I've received some very small (<0.000001) transactions in the last few days. They weren't from myself and I wasn't expecting them. Browsing the block chain, I see other address receiving such transactions as well. I find this very odd, as they are paying more in tx fee than the transaction itself. Is this some sort of probing attack, or is it just a misbehaving client? I hope nothing nefarious is happening. Does the client handle receiving transactions for yourself differently than other transactions? Is there any info leak here? I could see someone trying to probe clients with transactions to get info on which client owns what and then go into attack mode when a suitable target is found.

Here are a few examples of some blocks I noticed with these small transactions. The destination addresses seem to be used, so I don't think these are the change address. There are many more than these.
block 132736 has an output for 0.0000001
block 132738 has an output for 0.00000001
block 132751 has an output for 0.00000005
block 133374 has 3 outputs for 0.00000001
block 133431 has 2 outputs for 0.00000001

If anyone knows what's happening here, I'd be interested in the explanation.