With the countless number of free google services around, you might be forced to have more than just one google account. You might even have two gmail accounts for different purposes. I, for example, have a normal google account for this blog plus a couple of other google services I regularly use and another google apps account on which my business email is hosted. Sometimes I need to sign in to both accounts but switching between accounts will make one log out and log in countless times. Also, using different browsers to access your different google accounts isn’t the perfect solution. Did you know it’s possible to use to google account (or gmail accounts) at the same time on the same browser?
You do not need a browser add-on to get this done, just go to Google Account Multiple Sessions settings page. From this page you can turn on the settings that enable you to use two google accounts on the same browser at the same time.
After enabling multiple sign in for either of your accounts, you can switch between either of your google accounts by clicking on the arrow beside your email displayed at the top-right corner. It might be necessary to log out of your accounts for this change to take effect.