Real Estate Articles PLR is just what it sounds like...a site specializing in supllying you with private label articles specifically for the real estate niche.
I think this is a great concept because it gives you the opportunity of creating either a big content rich authority site, or to build your own network of smaller content sites, all around one big niche.
As niche markets go, real estate is one of the most profitable ones, with a ton of money being spent on a huge range of products and services.
There are lots of high paying keywords across many different sub niches related to this niche, and plenty of info products and affiliate programs to monetize your traffic.