Timelines are handy for all kinds of research. I find them personally helpful in genealogy research.
By going to a Timeline site, you can see what was going on in history at a given time. You can answer questions about what was happening at a certain time in history. Researching different times in history makes knowing about families so much more fun, and helps you understand what your forebears were dealing with in may ways - wars, disease, fashion, what people used to wear, eat, read, customs, and so much more.
You can also match what books were popular for different periods, and what people were talking about. These sites are interesting also just for themselves, or as a refresher to what you may have learned or not learned in high school or college.
Have another site you want to add here? Just put "Betsyanne Timeline Page Addition" in the address section of an email, and send your suggestion here: My Betsyanne Contact Page.