Your company can see where you have been if they want, but can't see what you post unless they look at the site itself. It is unlikely that they would as there is really not time or reason to do so. It is always possible to view what you are doing by remote desktop, but again typically the only reason to use remote desktop is to do installs or maintenance on the computers. Unless they suspect you of some illicit activity, it is really unlikely that they are going to see what you are doing here. If on the other hand you are being investigated for poor performance it is possible, that they may use evidence of your internet activities in some proceeding. I work in IT and contrary to what many believe we just don't typically monitor everything folks are doing. It is prohibitive to do so because of time and resources. It is very rare that I ever receive a request to do this and most of the time it involves email and not internet activity. While not always the case, if you are doing your job, no one cares what you are doing legally on the internet. That being said, I would check you local policies, but there is not reason to be paranoid.