Be very careful. It has become a common practice, for certain employers, to creep the walls or tweets of potential candidates for employment. We have all heard of this but does it really happen? In 2009, CareerBuilder.co.uk, surveyed over 450 employers and found the following:

“Of those who conduct online searches/background checks of job candidates, 43 per cent use search engines, 12 per cent use Facebook and 12 per cent use LinkedIn. Three per cent search blogs, while an additional 4 per cent follow candidates on Twitter.”

Now that was three years, ago, and with the rise in online use, these numbers may have increased. Of course there are privacy and anti-discriminatory laws in place to prevent the use of this information. However, in practice it would be hard to prove the actual use of social networking sites for hiring purposes.
Tips:
Check you privacy settings! Some people have their page completely open allowing for your “dirty digital laundry” to be exposed.

Personally, I have now made it so that

1) no one can post on my wall

2) anyone that tags a picture or check me in to a place must get approved by me prior to linking me to the post

There are many other things at the article below notes. You never know who is searching your profile. Do a google search on your name and see what comes up. I noticed that there are social sites that have information about me from 10 years ago still around! GET RID OF THEM!
Remember, you never know who is checking your digital signature so keep in mind that a picture (including profile) does say 1000 words.

http://www.guardian.co.uk/money/work-blog/2012/jan/30/facebook-timeline-...

http://www.careerbuilder.co.uk/UK/share/aboutus/pressreleasesdetail.aspx...