StumbleUpon passed the 25 million user mark earlier this week. Is it a mainstream social network yet?
StumbleUpon passed the 25 million user mark earlier this week — that’s about one million users every month since it announced it had reached 20 million users in October.
The discovery service has existed in some form since 2001. It accepted its first round of funding in 2006, was purchased by eBay in 2007 and became independent again in 2009.
At that point, it had about 5.5 million registered users. It’s been growing at a lightning rate since, nearly quadrupling its userbase in three years.