I am surprised how many people still think Twitter is a fad or a waste of time. I view Twitter — or some modified future version thereof — as everlasting. Most of all, the search function helps you tap into a real time conversation on just about any topic you want, including the lecture you just gave. Google is wonderful but it's hard to sort through the mess and figure out where the conversation is now. For sampling opinion on either movies or music, Twitter is essential, or even for researching a forthcoming blog post. Think of it as Google focused on one time-slice and giving the weight of crowd opinion no more than linear force. If an opinion is more common it will receive more tweets but otherwise your search brings up the splat, ordered by chronology, and thus it is more idiosyncratic than the first Google search page and often in a good way.
At least now, the people on Twitter are smarter on average than the people whose choices feed into Google. I am not sure that particular benefit will last forever,
If you can find some people worth following, so much the better. But the value of the medium doesn't much depend on what they had for breakfast.
Many people use Twitter to ask for advice; I have yet to learn how to do this well.