Some of us post their solutions to github or other free repositories. The main idea behind is Perhaps this will attract some potential employer.
There is nothing evil in this, however, if possible, DO NOT DO THIS, please. :)
Let me explain few points about it:
Your potential employer is mostly interested to see not exercises solutions, but rather your own projects, at least small - e.g. employer often wants to assess your ideas and your creativity. I know this for sure for I myself often conduct technical interviews for my company. BTW if you need ideas for larger projects, visit our PROJECT IDEAS LIST - working on such more advanced applications will greatly increase your skills and your karma for sure! :)
If some employer will ask you to show/prove your progress (some users told me this happened to them) - you have no problems pointing at your profile and, if necessary, show your sources logging into site.
Employers are usually very nervous about keeping their company secrets. When you get employed, you usually sign NDA. So when employer sees you posting information which also can be regarded as confidential - they may prefer avoid hiring you. This also is important about disclosing your previous employers information. Be very careful - read the Google's HR Laszlo Bock's article mentioning this.
Nasty thing is that published solutions drive some of our younger colleagues to try cheating with the site. There is not much harm (unless they pretend for certificate) in it, but if we can prevent people from doing wrong things - we probably should do this.
Anyway, please be sure that I could not restrict you in any way - I only ask / recommend... :)
And thank you for reading so far! Thank you for being with us!