What I'm thankful for: Gmail
I'm totally obsessive about my email. It is communication avenue number one for me and, frankly, it used to be a giant pain my my tuckus. Back then, in order to get the functionality I needed as well as the functionality I desired, I was stuck running my own mail server, webmail gateway (for when I was away from my normal PC), maintaining Spamasassin and using Microsoft Outlook as a client with a smattering of filters to keep some level of clarity.
Thanks to Gmail I dumped my webmail gateway (though I still run my own mail server, it exists largely as a pass-through) and with it a ton of administration headaches. Even as my email volume has risen dramatically, I spend almost zero time dealing with spam, and I spend no time maintaining spam filtering rules and software. Now I am a mail user rather than a mailsystem maintainer and, as a result, I'm able to dedicate more time to my actual work, rather than to the tools that support my work.
So, thanks this holiday to Google for Gmail. The webmail app that doesn't feel like webmail, and the first in a long string of Web 2.0 apps that allowed us all to look at and interact with the Internet in a host of new ways.