When is the last time you googled yourself? If you have posted information on the internet over the years, google and other search engines can find it. A few weeks ago I was involved with some job interviews and used google to find more background information about applicants.
Whatever information you have shared on the web will influence potential employers. It makes sense to reconsider posting something that may be a poor reflection of your character at some point in the future. You many not be aware of this but you probably already have an online portfolio of sorts that can be gathered together through search engines by anyone out there.
We know that the web has an archival history even though some sites or information may have been removed. (Way Back Machine can find web pages that are no longer active.) As digital citizens we need to recognize that we have a web presence the moment we share something. When you post to a public network it is open for the world to see.
Just as an experiment, try googling yourself to see what sort of web presence you have. What does your digital footprint look like? Will Richardson suggested at the May IT Summit conference in Saskatoon that we need to teach young people about their digital footprints and what it means to have a web presence. The future for our children and grandchildren involves realities we haven't imagined. Part of the reality will be what our children and grandchildren create. What their footprint will look like is hard to say, but one thing for certain is that it will be different from the network and connections we currently have access to.