What's these hidden folders doing here?

Example:
C:\Documents and Settings\my name\Programdata\Macromedia\Flash Player\macromedia.com\support\flashplayer\sys\#video.google.com

There is a bunch of folders under \flashplayer\sys. Seems there is one folder for many of the websites I once visited a long time ago. But I have deleted all the temp files, also temp Java files. But this is not deleted.

Can I safely delete this Macromedia directory?