@Jeremy Martin the Sec 121 exemption you're referring to actually requires that you meet two tests: the use test and the ownership test.

Be certain to test and validate any list.

Doesnt pass the sniff test to me.

They can look for recent damage and do moisture tests.  

It needs to pass the Does this Make Sense Test.

That being said, you can't beat the eye test.

Do an environmental test to ensure the ground is "clean".

Perc test on file for conventional septic system, and we may drill a well and bring back electric this year.

> Airdna had one I believe they retired (not Market Minder ... forgot the name - plotted a bunch of triangles in a matrix)> Mashvisor currently offers a heatmap feature for "Airbnb COC return" - cumbersome, but you can manually scroll across the US and look for green areas while pulling your hair out every time their interface freezes> I'm actually beta testing a new platform a company called STR Insights is launching that displays the same data in table form with a map feature as a bonus to double click into individual markets and see where high performing listings are locatedAll 3 are essentially doing the same thing: comparing average STR revenues (scraped from Airbnb/VRBO) to average home prices (scraped from Zillow, etc.) and converting them into a ratio.

Don't build it, before you start working it.Call 100 of those people every day for the first 30 days to build it.....missing a phone number, email them and get it, and then call them.Have a phone number, but no email, instagram, or fB, get those.Ask all of them to use and test your personal real estate app.At the end of the 30 days you should have 2000-3000 people in your database.