Sony does the microtransactions thing, but more and more people are coming onto Home all the time, especially with the ginnnormous Ps3growth lately--bigger audience means more people will be viewing the "ads" and so the company's sponsoring tem would pay more. Also, all the advertising done for games done on home is a "hidden" source of revenue that you cant directly tie to home when you look at the numbers.
That said, is it profitable? I'm sure that it is on a month to month kind of basis, but it will still take a couple of years for Sony to get their money back after the investments, programming, etc that is required for home, so i'm being realistic.