I'd be skeptical of someone, especially in IT, who has no online presence. I believe it is good to build up a brand around your name on the internet. You should be in control of what potential future employers see when they Google you. It is better for you to be in the top spot for your name then someone else talking about you, or something with the same name.
When I first joined the internet, I asked my parents if I could have a website on Geocities. They said no. I didn't listen and went behind their back to create it. I didn't have any info besides my first name, so there was no real harm (and I was smart enough not to meet up alone with random strangers, not that I was ever propositioned).
In 2001 I bought a domain named after me and blogged on it (although, it took years for me to admit it was a blog, since those had a bad stigma attached :) ). More recently I've posted the occasional technical entry. Because of this I've been cold called (well, e-mailed) from major companies asking if I want to interview.
It is 2009, nearly everyone has some sort of online presence now. It is unlikely you'll be targeted just for having your name out there. It is much more likely bad things will happen when a company you deal with is hacked and your information is stolen that way. Plus, you can use your presence as a defense. If I wasn't the top result on Google for my name, people might think I was an anti-semite author.
Andrew Hitchcock
