One of the first things I do when a new face strolls into the office, is jump on Google and start digging for dirt. The next person that reads your CV will probably (at some point or other) start digging around too. What impression would they get from the information that's available online?

Google

Google your first name. It's probably already in your Internet history, so you shouldn't have too much trouble there. Are you anywhere on the first few pages of results. You may or may not want to be, that's up to you. If you are anyway, check the sites and see what they say about you. There are a dozen or so automated sites that pick up Facebook, Twitter etc accounts, but just check what they're picking up. You might find some unexpected junk in there that you didn't think was public... Like an Amazon wish list you set up as a joke for your mates. Oops. Better delete that.

Google Images

Just double check the first few pages of images. Make sure you're happy with what's there, and if you're not, try to get rid of them.

Facebook

Even though your prospective new boss might not be your best buddy on Facebook, they'll at least be able to see your profile picture and maybe one or two from your, or your friend's albums. If you're out trying to get a job a white collar job, the photos of you crushing a beer can on you head don't make you look like a good laugh that will fit in the office. They'll make you look like a tool. Either delete them, untag your name from them, and change the little caption underneath to remove your name. If they're your mates pictures, fire them a quick message asking them to do the same. As well as searching Facebook for Facebook pictures, do the same through Google images. Search your name + 'facebook'.

[UPDATE] Check what is publicly available through http://zesty.ca/facebook/

Linkedin

Check your profile. Is it filled in? Is it up to date. Does it have a picture? Do you want a picture? Is there a link to your website? Do you have lots of amazing connections with lots of amazing people? Whatever you have to do... Do it. Plenty professional people use LinkedIn, and it's one place they might be looking. If you have connections with lots of random strange groups, consider ditching them. Remember that they could give a bad impression before you even walked through the door. In fact, you might not get the opportunity depending on what they dig up.

Twitter

Twitter is a tool for linking up with people, sharing content and a bit of chitter chatter. Depending on how you use Twitter, you'll send more of these than the other. Anyone that finds you Twitter account will probably have a quick glance down the first page or two of messages you've sent. I don't think you'll be hurting anyones feelings if you delete the retweet of "RT: OMG, check this monkey picking his nose. LOL xD. www.timewasters.com/monkey"... As funny as it was, it makes you look like you like farting around on Twitter all day. If you do, that's fine, just don't let your interviewer know. Delete the rubbish off the last few pages.

The Rest

Whatever profiles you have on whatever sites... Check the information available to the public and check that you're happy it's public.

Voicemail Message

This should be fairly obvious, but just double check your 'Please leave a message' message. If you reenacted the WAAASSSSSUPPPP advert, you're an idiot, change it. If you're expecting a professional call you might like to leave mobile number and email address. At least they know what else they can try. About once a week I hear answer machine messages where people just say "Jim Jimbleson". Our office telephone system (on initial setup) says "After the tone, please state your name" where it should say "Leave your voicemail greeting message". Call your own phone and check what the other person will hear.

That's about all I think. Leave a comment if I've left anything out, if you've ever left something online by accident, or if you've ever interviewed someone that you knew a little too much about!