IsDon is correct, however ALL HR departments and recruitment consultants these days are doing the same thing - they want to build your "social media/internet profile" and they use every tool they can to do this. There are also a host of new start up companies that specialise in trawling through the internet looking for your traces. They trawl through stuff like linked-in etc.
Examples of what not to do:
Have a pornographic email address.
Post anything to a website that could be regarded by ANYONE as extremist or bizarre (I once inherited an employee whose hobby was morris dancing seriously).
Let your hair down on your facebook page about what you did last night.
Post any opinion that could characterise you as angry, unbalanced, depressed, fixated or aggrieved.
Post anything that is not politically correct starting with admitting to not voting yes to SSM, being skeptical about climate change or confessing you think Pauline Hanson is sexy.
Trash your current or former employer on any website.
Please note that HR do not have a sense of humour. Please note that your mildly ingenious method of hiding your identity will not work either.
Ideally your profile should show absolute loyalty to you former employers, plain vanilla political and social attitudes, charity, chastity, prudence and similar virtues.