Here in the UK it’s summer holiday time and most children and their teachers are on a break from school. I call it a break but I know that many teachers still do work and preparation during this time, both in and away from their school buildings. At this time it is no surprise to see a dip in teacher activity on Twitter as the teachers take some time for themselves and their families, hopefully by enjoying a relaxing and well deserved holiday. What also happens though, and I have seen this in previous years, is that the drop in activity from individual teachers doesn’t just last through August but also into September. It seems that many teachers simply do not return to Twitter after the summer break. Why might this be? Well, of course, some of them may have moved on to new pastures and no longer feel a need for Twitter but I’m also sure that many just don’t feel a need or inclination to be quite so active as they used to be. For sure, there will also be other teachers coming on to Twitter and exploring it’s potential. So overall teacher activity is quite likely to increase over time and there’s little fear of the individual teacher feeling lonely or isolated on Twitter. What puzzles me though, is that we often hear time and again how good Twitter is for professional development. If that really is the case, why do so many teachers leave Twitter?