Wednesday, 3 p.m.: My friend Andrew Nystrom was at work in his office in Santa Monica, and my colleague David Sarno was hanging around his editor's desk at Times headquarters downtown.
I knew where they were thanks to a new smart phone feature on Facebook Inc.'s website.
Called Facebook Places, it lets you see exactly where your Facebook friends are whenever they engage the feature.
To let me and their other Facebook friends know where they were, Andrew and David simply had to click "Places" to check in. That's an especially easy thing to do on an iPhone because Places is built in to the Facebook app for Apple phones. On a BlackBerry or Android phone, the Web browser can be used to go to the Facebook site and check in there.
The feature can also use GPS on a smart phone to tell me which of my Places-enabled Facebook friends happen to be closest.
Not surprisingly, or interestingly, the ones who were closest to me while I was writing this column were, like David, right here in The Times building. I could have just as easily stood up and looked around to see who was there. But that would have been so analog.
It was like the early days of Twitter, when friends let you know every time they were, say, eating a sandwich. I didn't really care. Just like I'm not all that eager to know where that sandwich was being eaten.
So, the Places feature isn't very entertaining during the work week — unless you're friends with Eminem. He seems like a nice guy.
But the digital friend tracker really comes out of its shell on weekends.
That's when days are more likely to be filled with farmers markets, mimosa-themed brunches and trips to the beach, rather than nine hours, minimum, in front of a computer screen. Now I can spend those sunny days staring at a tinier screen, while keeping my Facebook posse constantly informed. Progress!
For bar-hoppers, the Places utility becomes especially obvious at night. If your friends are using the service, you can see at a glance who you're likely to run into during a night on the town, and perhaps avoid potentially embarrassing or even expensive situations.
Let's say I go to Dillon's Irish Pub in Hollywood and do a Places check-in. Maybe Andrew is at a concert at the nearby Henry Fonda Theater, and has not only checked in but also let his Facebook buddies know the concert is sold out.
Now I know I can skip going over there, where I might be tempted to buy an $80 scalped ticket.
Meanwhile, David might be dining at the Cat N' Fiddle Pub on Sunset Boulevard. When I'm bored with the football game on the big screen at Dillon's, I could head out to see David. I might even show up unannounced, which could be awkward, but, hey, he let his Facebook universe know where he was.
All this can be made possible by a quick scroll through my Places page, eliminating the need for numerous phone calls and text messages.
Well, that's the idea anyway. I put Places through its paces the first weekend after it was launched, but I was mostly alone. Even among my hundreds of tech-savvy, early-adopter friends, few checked in and the ones who did weren't making a habit of it.
Several start-ups are competing in this location-based social networking space and Facebook already works with many of them.
Foursquare, for one, is based around telling your friends where you are and competing to see who can check in from the most locations. Active users earn points and virtual merit badges for their efforts.
Now that Facebook has its own location feature for its 500 million users, it might seem that Foursquare could be hurting. It has only some 2.5 million users as it is.
But most of my friends now experimenting with Places continue to frequent Foursquare, perhaps because it has some advantages. For example, some restaurants offer mobile coupons exclusively to Foursquare users. And when a friend checks in from a venue near me using Foursquare, an alert pops up on my phone. Places doesn't have that.
Places does have a unique tool for noting which Facebook buddies are with me at a location, which is nice if they don't have a smart phone of their own. It's like tagging friends in a photo on a social networking site.
Of course, that can be abused. Somebody once tagged me in a picture of a hot dog. Similarly with Places, I can check people in from locales even if they are nowhere in the vicinity.
If you turn off the Places feature in your Facebook privacy settings, however, no one can tag you. Which is an especially good thing if you're staging your own version of "Ferris Bueller's Day Off." Sometimes you don't want to be found.