I concur with Oli. These types of questions should still be answered; after all, Ask Ubuntu is about Ubuntu regardless of the version, and there's nothing in the FAQ saying that these questions are offtopic.
One advantage that Ask Ubuntu has versus doing a regular online search is that it makes it easy to find relevant information if questions are tagged properly. As I understand, a major problem some people run into when trying to find solutions to their problems is that they find information that is for the wrong version. Oftentimes the problem is that this information is too out-of-date, but in other cases where people are looking for information regarding an older version of Ubuntu, they may run into stuff that is too up-to-date. One solution to this problem is that Ask Ubuntu has tags for the different versions of Ubuntu, which should be used to indicate that a given question has information that is relevant for version X, etc. We are in a unique position to provide users of obsolete versions support that is easy to locate and more likely to be relevant to them.
That being said, we should still gently remind these people that they should consider upgrading when it is convenient for them, even as we help them. After all, it gets harder to continue providing quality support for older versions of Ubuntu when fewer people are using them, and it takes away from our ability to help those out with newer, officially-supported versions.