I use pricing algorithms so my rates are different all the time.

To my knowledge, trulia/zillow use some sort of algorithm that aggregates prices.

I'm predicting instant book will become a larger part of the ranking algorithm for each platform and anyone who doens't have it turned on will see a drop in rankings and thus bookings.I'm very interested to see if you stick it out with booking.com @Julie McCoy I too had a few initial bookings but eventually turned it off as it was way more trouble than it was worth. 

We installed one pool alarm which not like you asked but loud enough to wake parents if any water activities within the pool:lifebuoy Pool Alarm System - Pool Motion Sensor with Advanced Algorithm - Smart Pool Alarm That is Application Controlled.

SEO takes a while and algorithms change often so it can sometimes be a moving target for new sites who haven't established much authority. 

You can also test cold interest stacks (like housing, renovation, credit) and retargeting interests (like people who engaged with your Page or Website) to give Facebook as large of audience size as possible and let the algorithm find the good ones.

Zillow Rent Zestimates is another option, but it admits it's not totally accurate, although its algorithms do take into account more of the items noted above.

You need an algorithm for IRR.

The algorithm would limit scores based on arbitrary absolute numbers, like $2,000,000.

There is an algorithm that we use to determine those properties and one that we spent thousands of dollars with engineers, programmers and designers putting together.