Investors have always played a big part in the Manhattan real estate market. Which, given that Manhattan condominiums remain one of the premier real estate investments this side of the private island, makes plenty of sense. But while investors hoovering up NYC condominiums isn't news, the number of investors currently buying up Manhattan condos -- and the percentage of the Manhattan condo market that those investors currently represent -- is looking more and more like news. And in this moderately slow and still-recovering Manhattan condominium marketplace, investors are making a bigger impact than ever. Which is nice, but what impact will it have on those -- to take one example -- who are browsing Upper East Side condominium listings less to find an investment than in hopes of actually moving to the Upper East Side?