Slowing Skype momentum

Readers may have noted that from time to time I report on traffic observations for Skype. I collect these at regular intervals (ideally every day, but sometimes only when I can remember to do so). The last four I have taken (23rd, 26th, 27th and 31st May) all show Skype MoU per day below 40m (vs. an average of 42m in March and April), and the most recent observation showed downloads just above 305k per day (vs. an average of 479k in March and April).