Lifehacker is a cool website -- you can find how-to articles on just about anything from kitchen to computing. I've used it a bunch of times to help me figure out how to do several things with my computer, for example.
However, even though our site has a similar name, our scope is NOT the same as that of Lifehacker.
Our site (for the moment) only takes questions about physical problems, for example. Therefore, questions about booting Ubuntu are off-topic, even though you might find the answer at Lifehacker.*
This is not to say that I think that questions involving tech are off-topic; a question about cleaning a dirty computer screen, for example, is on-topic.
I don't either mean to say that anything found on Lifehacker is off-topic; like I said, they also have solutions to "real-life, physical problems," such as one or two alternate methods for sharpening knives.
* We have other sites that serve this purpose: Web Apps, Super User, Android, Ask Different, Ask Ubuntu, Unix & Linux, and a few others.