reports 1 million users – post Yahoo! growth tops all of Digg founder Joshua Schachter just posted to the blog that the service has registered its 1 millionth user. Schachter says that number has more than tripled in the last 9 months. The company was acquired by Yahoo! ten months ago, in December of 2005.

Digg, by comparison, reported last month that it has a half million registered users. While came online in late 2003, Digg launched in December of 2004. That means that had 300k users in its first two years and Digg has 500k in its first two years. The impact of the Yahoo! acquisition has also been big, though – with gaining more than 600k in the last 9 months.

In other words, for all its high profile expansion, the impact of being acquired by Yahoo! may have brought more users to than everything Digg’s done for itself so far. In some ways the sites are very different and used for different purposes, but the comparison is interesting.

All of this can be compared as well to Yahoo! acquired (in March 2005) Flickr with 2.5 million registered users. Flickr is regularly referred to as the small upstart innovator in the photo sharing space, but it has twice as many users as the venerable and five times as many as the precocious Digg.

This tells me that there is plenty of room for more services to provide these types of services, despite the exhaustion some of us feel every time a new one emerges. It also indicates that there is something far more interesting about Digg than the size of its contributing users.

Regardless of all of that, congratulations to Schachter, and Yahoo! for passing this milestone in social bookmarking.