Who made a mark in May 2014?

I'm still trying to develop a new way of doing "Who's made a mark". I'm now thinking along the lines of a once a month round-up complemented by more frequent posts of new things to look at via my Facebook Page. This seems to work better for me as it spaces out the effort involved.

That said I still need to work on timing - this was supposed to be published last Sunday - but I ran out of steam