These days I have had experience with three timeline applications: FriendFeeder, Plurk and Dipity. With them you can create personal timeline or timelines in different areas.
FriendFeeder collects information from social sites for news, bookmarking, bloging/ microbloging, video, photos, music. From an educational point of view FriendFeeder can be a great possibility for class/course resources' capturing and sharing and the students' work is so visible and transparent. I think that it can be used as a learning ePortfolio (personal, group/course/class).
Plurk is a social journal of everyday activities which can be shared with friends, family and fans. It has functions similar to a microblog, but possesses more innovative features: visual representation of timeline events, for each event messages can be send and received ,
motivated karma, customization by adding post links, photos, and videos, mobile version of your site. The Plurking is so amazing :). It can be used for event and learning activities planing, as a presentation tool of events, or as a communication tool.
Dipity allows the creation of a personal timeline, blog post timeline, events timeline, product history timeline, company history timeline and so on. Timelines can be created automatically by using existing accounts for Flickr, Twitter, Last.fm, or any RSS feed or manually. While FriendFeeder and Plurk are not designed especially for educational purposes, Dipity has a function focused on class timelines building. So I have selected some interesting Dipity timelines with educational value:

Important Events in Internet History: 1994-2004
History of Technology
History of the Personal Computer
Sony Computer Entertainment
history of 3D hardware + Software
Timeline about SolidWorks
AutoCAD Product