When I tell people about ShellSink, many of them say, "hey, that's a great idea!" Then the little sysadmin perched on their shoulder crosses her arms and shakes her head. "Tsk, tsk. Storing your shell history on a remote server is not secure!", she says. This is absolutely true. Not only is your bash history passed via an insecure Http connection, but then it is stored unencrypted on Google's servers where a rogue Google employee, someone who hacked Google, or a rogue ShellSink admin could access them. Don't use shellsink on a system that needs to be ultimately secure!
However, Shellsink
is safe to use. If you use Google for email, calendar, documents, etc. then you already trust them with information that is probably more sensitive than your shell history. And if you don't trust me you can download the ShellSink source code and spin up your own server using Google's AppEngine. In any case you should still take some basic precautions. Most importantly, never use inline passwords!! ShellSink will send anything your bash history captures.
Here are several ways to safeguard yourself against sending sensitive information to ShellSink.
One technique is to add the following to your .bashrc:
HISTCONTROL=ignorespace;
Now any command you precede with a space will NOT be captured by the history, and thus will not be sent to the ShellSink server.
Another technique is to add the following to your .bashrc:
HISTIGNORE="netstat*:sqlplus*"
In this example any command that starts with netstat or sqlplus will automatically be ignored by the shell history and ShellSink. Both these techniques give you different granularity control over what gets sent to ShellSink. The first technique works on a per command basis and the second covers all commands.
Finally, there is the nuclear option:
shellsink-client -d
This completely disables ShellSink for all terminals. I don't really have much use for this one, but when you start to do something that you are ultra paranoid about, this is one way to be sure nothing is leaving your computer via ShellSink. To re-enable ShellSink simply do this:
shellsink-client -e
Release 0.2.2 adds a new feature. You can add tags to a command at the same time as you execute it. This is achieved by using inline comments. Here is an example: 
Shellsink has been a pet project of my for the last few months, and it has been fun to put something new out there just to see how people react. My main goal of course was to build something useful. What I didn't anticipate was that I would have to begin paying for hosting so soon. Unfortunately Google has rolled out the non free portion of app engine, and they have announced resulting changes to the service. I had hoped that ad revenue on the shellsink site would pay for whatever app engine hosting costs were incurred, but since 99% of use is at the command line, actually very very few ad impressions are viewed on the site.
On the same day that our government gets an upgrade, ShellSink gets an upgrade. Specifically, a new version of the server is live! The changes are all performance related and it enables me to bring the client behavior into line with the way google has designed app engine to scale. That is, to make lots of very simple requests instead of fewer complex requests. 
