What’s a tumblelog, in the first place:
A tumblelog (also known as a tlog or tumblog) is a variation of a blog that favors short-form, mixed-media posts over the longer editorial posts frequently associated with blogging. Common post formats found on tumblelogs include links, photos, quotes, dialogues, and video. Unlike blogs, tumblelogs are frequently used to share the author’s creations, discoveries, or experiences while providing little or no commentary.
Tumblelogs usually consist of a stream of ideas (and media) while one is online or even offline. While blogs usually are long post, tumblelogs are short–just anything you want to share.
In the words of Tumblr:
To make a simple analogy: If blogs are journals, tumblelogs are scrapbooks.
I particularly loved the system behind tumblr to build my tumblelog upon. I received an invitation to try out tumblr long before, but I actually tried out the service only since last week. Having some spare domain names, I decided to put them up to good use and give tumblr a try.