Got this in the TiddlyWiki mailing list.

If you have a gmail account, you can use the gspace firefox extension to save/retrieve your TiddlyWiki to/from your gmail account. Your gmail account will look like an ftp host. It is suprisingly fast and simple. You will want to set up a filter that automatically places these files into your archive.

You might visit Mozilla Addons to get more information. This plugin reminds me of GMail Drive – it created a “disk” in My Computer that hooked up with your GMail account. GSpace presents your account through an FTP-style interface. Looks cool.

A cookie for Firefox and another for Google.

BTW, I’m not going to use it because I believe in the phone toh sirf baat karne ke liye hote hai principle. Same applies to GMail.