I definitely think that Wikipedia lives up to its name. The prefix "wiki" means quick in Hawaiian. For me at least, wikipedia certainly serves as a quick reference source. I have found myself "wikipedia-ing" topics in the middle of conversations in order to look up something that has been questioned, or to learn more about what is being discussed in a quick and discreet manner. Now that wikipedia can be accessed from smart phones and there are even wikipedia apps, it makes the process even quicker. Even before that though, wikipedia typically comes up as one of the first results on Google when you search for nearly anything. I think people like that it is so convenient and easy to maneuver.
In terms of school and major research papers, I will typically use wikipedia as a general starting point. From there, I will research more about the specific facts I find on wikipedia to certify that they are correct and to also elaborate on them. Although I have been told by many teachers that Wikipedia is not a reliable source, I think that for the most part, the editors monitor the pages very well. A friend one time posted something on the Fordham sports page that was blatantly wrong just to see how long it would take for it to be removed. The erroneous fact was gone within 5 minutes of it being posted. I understand that if I am writing a paper I could happen to catch the page within the 5 minutes that it takes the editors to get to it, but I think the chances of this happening are probably slim.
My mom owns a complete encyclopedia set that consists of 29 books. We keep them on a shelf in our basement considering that they are now nearly obsolete. I remember using those books for projects and papers up until about 7th or 8th grade. After that I do not recall searching through them for facts, instead I probably "wikipedia-ed" the stuff I needed to know.