I think you are looking at this backwards. How many listings are there on Craigslist for a given city? 100, 200, 500, 1000? (I know city dependent)
There is absolutely no reason that PadMapper cannot call them on the phone, and ask them to list with PadMapper. They can make it trivially easy supporting email, phone, or fax listings. They can sell them on using PadMapper.
Many apartments are owned by Real Estate Investment Trusts (REITs) there are dozens (not hundreds) of those. You can sell the REIT on the concept of easy listings that are so much better/cleaner/easier than Craigslist.
Craigslist was created when near every apartment was listed in the Classified Ads in the print newspaper. That wasn't "lock in" it was an opportunity, they sold these folks on lower costs (since Classifieds were a money fund for newspapers) Landlords hated the extortionate prices that the newspapers charged but they didn't have an alternative, Craigslist gave them that alternative, they moved.
So the 'answer' here is to actually build a classifieds business around rental space. That takes more than slinging some node.js and scraping other sites. Granted its 'easier' for a technical person to do it that way, but its not a 'sustainable' way of doing it.
That wasn't "lock in" it was an opportunity, they sold these folks on lower costs (since Classifieds were a money fund for newspapers) Landlords hated the extortionate prices that the newspapers charged but they didn't have an alternative, Craigslist gave them that alternative, they moved.
But you are using an example in which there was a clear downside to using the existing listing model. The price. If you are a landlord and you have no problem renting out apartments in a reasonable amount of time on Craigslist, and it's free, what exactly can another site offer that is "better"?
They are already getting their apartments rented, there is minimal overhead to using Craigslist. You can't compete with Craigslist on price, unless you are actually giving landlords money for listing on your site. And trying to say "It's easier for users to find your properties." doesn't help if they aren't having a problem with renting out their properties.
There is absolutely no reason that PadMapper cannot call them on the phone, and ask them to list with PadMapper. They can make it trivially easy supporting email, phone, or fax listings. They can sell them on using PadMapper.
Many apartments are owned by Real Estate Investment Trusts (REITs) there are dozens (not hundreds) of those. You can sell the REIT on the concept of easy listings that are so much better/cleaner/easier than Craigslist.
Craigslist was created when near every apartment was listed in the Classified Ads in the print newspaper. That wasn't "lock in" it was an opportunity, they sold these folks on lower costs (since Classifieds were a money fund for newspapers) Landlords hated the extortionate prices that the newspapers charged but they didn't have an alternative, Craigslist gave them that alternative, they moved.
So the 'answer' here is to actually build a classifieds business around rental space. That takes more than slinging some node.js and scraping other sites. Granted its 'easier' for a technical person to do it that way, but its not a 'sustainable' way of doing it.