I have saved to my public Dropbox folder some custom icons (this folder was recommended by the icon developer).
The icons can be used and viewed on Google Maps when using IE but not using FF 8.0.
That is a problem with CORS (Cross-Origin Resource Sharing).
See this MozillaZine forum thread "My own Google Map icons are not visible in Firefox 8":
Yes, I have tried creating an .htaccess file and saving it in the public folder of Dropbox, where my icons are hosted, but this has not worked for me, nor for many other FF 8 users.
Alright FF8 enabled CORS.
What about file sharing services like Dropbox where we can't upload a .htaccess file to change the "Access-Control-Allow-Origin".
Now Dropbox is pretty useless on Firefox8, should Dropbox change his policy just for Firefox8 ?
I found out even icons hosted on Google Sites or Google Code are not working...