Twitter the micro-blogging site needs no introduction. Like Google, Amazon and Facebook, Twitter is also an element of Internet. Micro-Blogging may be a new concept but blogging is not.
Blogging has been in the market for quite some time now. Blogger and Wordpress have ruled that market but now we have light blogging concept which means that we want only the blog with some social element and no complicated operations. Tumblr and Posterous are two big players in that market now.
Blogger has the JavaScript support advantage. While Wordpress don't offer that in free. On the other hands Tumblr and Posterous focus only on post and social. So they become a light blogging tool. So you are not thinking of making money out of your blog, Tumblr is the best site to get your blog on.
Enterprises have also started using Tumblr and not Wordpress as they were doing earlier. Wordpress have been enterprise choice for many years but now Tumblr making growth in that sector. Blogger is more of a personal blog choice with the best feature for an individual to have a free blog. But when it comes to a professional blog Wordpress has been the choice and now Tumblr challenging that position.
It may take many years to beat Wordpress but Tumblr has for sure emerged as an tough opponent.