Web site Card.ly allows you to collect all of your contact information—online and off—into one simple, linkable "business card" you can share with anyone.
The site's pretty simple. You just sign up, fill in whatever information you want to pull into a centralised "business card", and you're ready to go. When you're finished, you'll get a personalised link that looks something like http://card.ly/lifehacker. You can simply share that link with anyone you want to stay updated with you, or, if you really like it, Card.ly provides various embeddable options for placing your vCard on your web site, in your email, or anywhere you want to include it.
Even though this is the sort of thing that it seems most people use the likes of Facebook for these days, Card.ly is a fun and simple idea executed well.