Ever since I’ve been old enough to leave the house on my own, my mom has always followed “goodbye” with “call me when you get there!” It never mattered if I was going down the street or 500 miles away, it was always the same.

Since joining foursquare, I’ve longed for a way for my mom to be on the service so she’d know I was safe just by watching my checkins. With her eight-year-old phone and complete inability to understand even the whole “texty” thing, it’s clear that’s not going to happen.

Now it doesn’t have to, thanks to a brilliant new foursquare API app called HashtagMom. When you add “#mom” to a check-in, it automatically gives her a call, lets her know you’re safe and reads her whatever shout you added to the check-in.

She even has the option to leave a message for you that will be delivered to your email.

If your mom is a little more tech-savvy and understands “texty,” you can opt to have HashtagMom simply send her a text instead of calling.

This is a wonderful idea because it addresses every mother’s greatest fear in a way that’s convenient and easy for us to integrate into something we’re doing anyway. Now I just need a HashtagWife service that sends my wife a text that says “I’m at the grocery store, do we need anything?”

What do you think of HashtagMom? Would you use it or would it just annoy your mom that you didn’t take the time to call yourself?

We’ve seen a number of services that send you some bit of useful information when you check in on foursquare. This content is valuable because it’s incredibly relevant, based on the place you’re currently visiting. What if you could extend that to get something relevant and useful when you add a venue to your to-do list?

ReserveMyCity has come up with a perfect way to “re-program the to-do button” to make it do just that. When you add a restaurant to your to-do list, ReserveMyCity sends you a link to make a reservation there.

It’s a simple concept, but it’s a first to take action after you’ve added something to your to-do list instead of checking in. It helps to close the loop between “I want to do this” and “I’m going to do this.”

I’ve long thought it was a no-brainer that foursquare would eventually add reservation links directly to venue pages, but it turns out that’s not likely since the most popular reservation provider doesn’t have an API. The best they can offer is a huge Excel file of their 20,000+ restaurants. ReserveMyCity has done the hard work of matching those restaurants to actual foursquare venues. It’s a manual process that simply doesn’t fit well with foursquare’s API-centric approach to, well, everything.

ReserveMyCity is trying to build a critical mass of users with which to launch the service. Once 500 users sign up (by connecting their foursquare accounts) they’ll switch the service on for everyone. The five users who refer the most signups will each get a $25 American Express Gift Card, so it pays to get your friends to register.

What do you think of the concept? What other functions would you like to see when you add a place to your to-do list?

NOTE: This post has been heavily edited to remove all references to the reservations provider that ReserveMyCity is linking to. I will never understand lawyers and it’s clear they will never understand the internet.

No matter what privacy measures foursquare has in place, there are some people who will never be comfortable constantly feeding their location into foursquare’s massive database. But thanks to that massive location database, there’s no better app for tracking the places you’ve been.

That’s why former Flickr developer Aaron Straup Cope has created Privatesquare at the Near Future Laboratory. It’s a self-hosted system that pulls from foursquare’s location database, but lets you check-in without sharing your whereabouts with foursquare. Since it’s on your own server, the data is all stored privately, but you can choose to share certain check-ins with foursquare (and then on to Twitter or Facebook).

“I don’t tell foursquare about a lot of stuff simply because I’m not comfortable putting that data in to their sandbox,” says Cope in a blog post. “So as much as anything privatesquare is about making a place to file those things away safely for future consideration. A kind of personal zone of safekeeping.”

Privatesquare also introduces a few unique tags to go with each check-in. “I am here” and “I was there” are the most similar to foursquare’s current check-in model, while “I want to go there” is similar to foursquare’s to-do list. The “Again,” “Again Again,” “Again Maybe” and “Again Never” offer a way to track how you felt about a place instead of simply saying you were there. Eventually you could create a list of the places you’ve tagged “Again Again,” for example, and send it to a friend as recommendations for a trip.

If you want to try Privatesquare yourself, you’ll need to install it on your own server. Everything is available on Github. The installation instructions call for a certain level of geekery, but don’t appear too difficult if you’re used to working with databases and OAuth. There’s currently no way to view or export your history without digging directly into the database.

Privatesquare could be a nice option for folks who aren’t comfortable sharing with foursquare. For me, the privacy options are just fine, but can understand why there are some who would prefer to keep everything to themselves.

If you happen to give Privatesquare a try, let us know what you think in the comments.