Sure, you could always use Twitter Tracking, but if you value your text messages, or have trouble with the IM client, it's hard to follow. There was once a way to find people through your Gmail contacts, but that's been disabled. Enter Tweet Scan, which allows you to search for up to five keywords and have their results delivered by email.
A quick scan of Second Life turns up many people I don't have on my list. I was also able to sift through tweets about Massively, to see what our readers think. While it's not perfect, and some results will be erroneous, it can certainly make it easier to find your friends. Don't forget to sign up for inbox delivery!