[caption id="attachment_22774" align="aligncenter" width="468" caption="An example of a Foursquare venue webpage"]
What's the appeal? Well, more and more venues are offering specials to those who check in, such as a free coffee every second check-in or 10% of a book in a bookstore. You can also leave tips at venues, which I found invaluable when I lived in America for three months last fall. I used Foursquare tips to see what the best places to eat, buy books and hang out were. My check-ins are only visible to people I'm 'friends' with, those who I expressly allow to see my profile. In return for accepting their request, I can see where my friends are, and there's been more than one occasion where I've seen a friend checked in somewhere, and then texted them to see if they wanted to grab dinner.
Obviously you should be very careful about accepting friend requests on Foursquare, as these people can see your current location.
So, even though there is a shift in how we view online privacy, it's still very possible to protect yourself online. The best way of protecting yourself online is to simply know the ins and outs of the services you're using, and specifically know how to navigate their privacy settings. Become familiar with Facebook's privacy settings (which lets you preview how your profile looks to outsiders) and also Twitter's settings pane. Especially keep an eye on Facebook's app permissions pane and Twitter's one, where all the third-party applications you've previously given access permission to your profile are listed. Revoke access for the ones you no longer use.
[caption id="attachment_22775" align="aligncenter" width="648" caption="Keep a firm hand on your privacy on social networks like Facebook"]
You know what they say: knowledge is power, and it's imperative that we, as internet users, set our own rules for how we use the internet. We shouldn't have to use all these great technologies at the expense of our privacy.