Chrome: Opening a ton of tabs in your browser can have disastrous effects on your productivity (and the stability of low-powered systems, like netbooks). Limit yourself with the Controlled Multi-Tab Browsing extension.
We've already mentioned how it's probably a good idea to limit your open tabs before, but you can really enforce that with Controlled Multi-Tab Browsing. Just install it, set your tab limit (pinned tabs don't count), and browse away. When you reach your tab limit and try to open a new one, it will alert you and tell you that you've reached your limit, and won't let you open that new tab until you've closed something else. Whether you're prone to getting distracted by all your open tabs or just trying to prevent crashes on your low-powered netbook, this is a pretty nice help.
It's worth noting that in the previous article we mentioned No More Tabs as a solution for Chrome, which takes the different (and slightly more annoying) approach of closing your oldest tab every time you try to open a new one. It's certainly effective, but probably boosts frustration for most people instead of productivity, so we decided we should mention this nicer alternative.
Controlled Multi-Tab Browsing is a free download, works wherever Google Chrome does.