Automating property sale/information follow-ups

[Peter R.]

Does anyone use software for this?

As in, you see a property you like but it's under contract and you just want to know if it comes back on the market.  Or if you see a property for sale that you're not going to pursue but would be interested to know what it sold for.

Or you're somewhat interested in a property but only if it drops below a certain threshold price.

Sometimes I just drive by a property and think "I'd like to know if that ever pops on the market."

What do you use for this, if anything?