The Toronto-based real estate classified site RentCompass has launched a new Facebook app to complement the mobile apps it already has.

The basic concept behind RentCompass is nothing we haven’t seen before – a Google Map with available rentals appearing as house icons. Click any item to go to the property’s details page, which includes the usual goodies – pictures, contact info, floor plans. But in the relatively smaller Canadian market, a small fish can make a bigger splash.

RentCompass has so far been available as a website and as a geo-smart mobile app that shows you apartments in the vicinity of where you are at the moment – i.e., walk down the street and see what’s for rent. It’s available for the iPhone and Android phones.

The Facebook app basically puts the standalone app’s functionality into Facebook. Once inside the the social network’s all-encompassing world, you can like, share and comment on a rental, as well as ask your Facebook friends their opinions too. Given the popularity of Facebook for mobile, it’s a good move by RentCompass.

The company also has a presence on Twitter (with its own app too), but the tweets are just a feed of every new property appearing on the website; it’s not location savvy, making it more of a promotional ploy than a truly functional addition to the RentCompass family.

Listing and searching rentals are free on RentCompass. The company says it’s the first mobile service in Canada for rental apartments and the number one downloaded app in Canada for rental searching.

This isn’t exactly a Canada story, but we were interested to see where Canada placed in terms of property website reach. Property Portal Watch’s Simon Baker put together the list, which found Australia’s RealEstate.com.au in the clear lead, reaching 17 percent of the country’s population of 22 million people. AtHome.lu in Luxembourg and ImmoWeb.be in Belgium also scored high with 14 percent reach.

On the other end of the scale, Japan, China, Brazil and Mexico have relatively small Internet penetration, Baker says, and therefore the online real estate reach is smaller (none of them scored more than 2 percent reach in his survey).

It should be noted that Baker looked at unique visitors to a site and compared it to the overall population of the country and not the number of Internet users which, for Western-oriented countries ,wouldn’t make that much of a difference, but could unfairly penalize developing nations.

So where did Canada fall out? Pretty much right in the middle. The leading site was Realtor.ca which reached 7.1 percent of Canadian consumers.