ReadWriteWeb

Slideshare is growing and may even have become the leading pure play online presentations app [Update: Zoli Erdos points out in the comments that Slideshare doesn't allow you to create online presentations, only share them - which is a key point that I forgot to mention initially]. Two years ago I lamented the shortage of 'online powerpoint' services and noted that it was a product category "up for grabs" in the Web Office market. But now it is flourishing - Web Office leaders Google and Zoho both have good online slideshow offerings and there is no shortage of other startups doing it. But Slideshare is the service that is grabbing attention, perhaps due to its focus on sharing and community.