Timelines are excellent for visualising change over time, but most timeline generators limit you to a single timeline. Web application Preceden features parallel timelines and accompanying charts.
At Preceden you can create multiple unique timelines by adding layers to your initial timeline. In the example image above, a company's growth is charted by the stages of the project they are designing, when employees joined the company, and the monthly visitors to the company website with all information displayed in parallel so you can easily see the connections between different segments of the data.
You can share charts for public browsing or keep them private for internal use. Timelines can be generated using spans of time ranging from years down to seconds. Preceden is a free service that requires a sign up — no email confirmation — to use. Have a favourite tool for generating timelines or other visual aids? Let's hear about it in the comments.