Tumblr, the hip blogging and curation platform based in New York City, announced today that it has raised a new round of venture capital. Not yet four years old, Tumblr hosts far fewer bloggers and website visitors than its rival WordPress, but serves up more than twice as many total pageviews.

Financial documents and the company’s blog indicate that the round was for $30 million, from a very impressive list of investors: Spark Capital (backers of Twitter, Aviary, GDGT, Next New Networks, and others), Union Square Ventures (backers of Etsy, Boxee, Disqus, Foursquare, GetGlue, Meetup and more) and as new investors, ultra-heavyweights Sequoia Capital (investors in Google, Apple, YouTube, PayPal, Zappos, RackSpace, Yahoo and many more). Tumblr has always been hot, but when a startup gets Sequoia Capital money and connections, it has entered a new echelon in the venture-funded tech world.

Comparing Tumblr and WordPress

How big is Tumblr compared to WordPress? Automattic’s Matt Mullenweg, founder of WordPress, told TechCrunch last week that his network is “currently getting about 300 million unique visitors on WordPress.com a month.” Traffic analysts Quantcast estimate that the whole Automattic network sees almost 500 million monthly visitors.

Quantcast estimates that Tumblr sees 48.5 million unique visitors each month on its network. So in unique visitors, WordPress is at least six to 10 times as big as Tumblr.

Mocking Tumblr is for losers. See our article, Why a Day of Tumblr Down Time Matters to the Entire Web & World

How many blog publishers does each network have? WordPress says it has 30 million, Tumblr said today it has 11 million.

But pageviews? Quantcast estimates that WordPress serves up 1.4 billion pageviews each month. Tumblr, it estimates, sees about 3 billion.

In other words, WordPress has many more publishers and far more site visitors, but people who visit Tumblr blogs view far more pages per person and twice as many pages in total.

At the same time, analytics provider Postrank concludes that WordPress and Blogger.com blogs get far more off-site social media engagement that Tumblr blogs do.

Pick your metric – what matters most? Probably pageviews.

Tumblr has now raised a total of $40 million, surpassing the $30 million WordPress parent company Automattic raised almost three years ago. Automattic is believed to bring in about $10 million per year in revenue, again according to TechCrunch last week. No revenue numbers have been estimated for Tumblr, but the company is presumably monetizing the growing number of blogs it’s hosting for big media companies. That’s similar to the business that Automattic is in, though much smaller.

Other competitors include SquareSpace, Acquia and SixApart. None are as easy to use as Tumblr is, however.

Disclosure: The author of this post loves WordPress and has never been able to get into Tumblr. Clearly a lot of other people have, though.