The wallet owner isn't doing anything. He is just receiving coins.
I could send one satoshi to each of the top 100 addresses in terms of BTC and you could do the same.
The mentioned address is used as a target for spam not doing the spam.
Yes. And this is usually done by those mixing services to hide who the real recipient of coins is (send a few satoshi to random addresses and hope that anyone tracking will focus on the random addresses, especially if they already have large balances, rather than the real address which is amongst them).
Hum, that is interest. Didn't know about that. Makes sense.
One of than https://blockchain.info/address/1AhTjUMztCihiTyA4K6E3QEpobjWLwKhkR have received a large amount from this one https://blockchain.info/pt/address/1GSFLSZJsGxdxKxNLQsGCYWi7WBqqxGHiW
That has received a large amount from this address: 1AhTjUMztCihiTyA4K6E3QEpobjWLwKhkR That I think was from a defunct exchange (2015-01-29). And most of the transactions usually send dust to big account.