Twitter can, or will, be able to tell where you tweet from, the company announced on Thursday. The company is giving third-party developers access before they enable the feature on Twitter.com. They will, however add the feature, and it will, most importantly, be opt-in. That’s important, because there are privacy implications. And that’s why it’s a good decision to make this feature opt-in. Of course, location-based services (LBS) are a hot trend, so it makes sense that Twitter would want to hop onto the bandwagon.