Part of building a good network involves regularly touching base with certain people, and it doesn't hurt to extend that idea to your personal life. TinyBlu is a simple web app that reminds you when it's been too long since you last spoke to someone.
Here's how it works. You add a person as a "lifeline" and classify them into a group. You are also prompted to set how many days should pass without contact before TinyBlu reminds you to get in touch.
Click the Update button for any lifeline to add details about when you last met, what you did, add any notes, and even add other participants from your lifelines. The data is represented in a bar with green and red colours, and matching emoticons, to tell you at a glance who you should contact. You'll also get a reminder email from TinyBlu if you enable that option.
TinyBlu's simplicity sets it apart from other such apps, and it doesn't require access to any of your private data on email or social networks.