So ... I've done the task for this which is searching for myself in an incognito mode and am pleased to say that nothing unexpected came up! Which didn't surprise me because I've always been aware that anything I put online is "out there" so have always been a bit cautious. In fact, this is why my Twitter handle is @bcb567 ... when I first signed up to Twitter, I wasn't convinced about it's usefulness or practicalities but I was at a conference and wanted to join in. So I made it something that didn't immediately identify me ... in retrospect and considering how useful Twitter can be, I think I would have just gone for my own name.
I also don't use different names or different information for the various sites I'm on ... so I am "me" on Twitter, Facebook, LinkedIn, Goodreads and Pinterest. Plus anything else I may have signed up for but have forgotten about!
I do belong to a couple of groups on LinkedIn and occasionally make comments but I'm not sure how useful it is as a means of finding contacts for employment and advancement opportunities. I know potential employers look at it but I don't know anyone who has actually found employment via the site. That said, I need to update my profile ... so that's a task for this weekend and the hyperlink in the MOOC has some excellent suggestions.
I'm also registered on About.Me but have never taken it any further than that. I sometimes feel that my life is swamped by all this online stuff ... the need to update profiles, tweet, post images, write blogs, etc. If it was on one site that would be fine but there are just so many of them now. I haven't added anything to my Pinterest boards for a while, partly because I'm so busy doing other things ... including reading books, something us school librarians do like to do from time to time!
As for "my professional brand" ... I would like to think that it's one of a Chartered librarian, experienced in school libraries, and passionate about the value and benefits that all libraries can bring to every section of the community. An organiser, someone who is reliable and gets things done, who is committed to CPD and supports colleagues, and who looks for opportunities to promote and advocate for libraries.
But I guess you'd be better off asking the people who know me what my brand is ....