By default PsychoPy attempts to ping this webserver each time you launch the application. This can be turned off in preferences but please don't! See Privacy Information for details.
The statistics below underestimate usage in the following ways:
Unfortunately, usage data for Dec 2013 and most of Jan 2014 were lost in a database failure.
NB: I suspect Linux users are actually a higher proportion than this, but they are especially likely to run Psychopy scripts without launching the actual application (so their stats are not recorded).
The only information sent to the server is the version of PsychoPy you're using, and info about your operating system. There is nothing that identifies you (e.g. username) or provides any personal information about you. The IP address is also received (as with any time you access a web page from your browser) and is used only identify 'unique' users.
(NB. Every time you look at any web page in your browser you provide the owner of that page with much more information than this!)
The information received will only ever be used for the development of PsychoPy. It will never ever be sold or passed on to other companies for other purposes.