Parkingspots.com does exactly what their URL suggests and this alone should help them to generate traffic without having to pay a penny for advertising.
The site is an online marketplace where owners of parking spots across the country can rent them out to those in need of a space to park their car. Parkingspots is currently available in Canada and in the US and it provides users with a number of ways to filter their search for the ideal space. You can either enter a zip code and have a list of spaces generated for you, search by city, or by using a handy integrated Google map. If there isn’t currently a parking spot in the place you are looking for, you can also request to be alerted by email when a place opens up.
Parkingspots.com In Their Own Words
“Welcome to Parkingspots.com! – A virtual parking marketplace. We take the complication out of finding your ideal parking spot thru our easy to navigate parking spot search tools. Locate your ideal parking spot by city, by postal or zip or using Google maps.”
Why Parkingspots.com It Might Be A Killer
The domain name alone should help them to spread the word without having to fork any money over to Google for search placement. The site is also well designed, easy to use and will appeal to anyone in need of a parking space.
Some Questions About Parkingspots.com
Have they considered trying to encourage more user interaction and feedback? Perhaps they could rank the best parking places in major cities or allow users to rank their favorite spaces? 
