Anthony Ha points out Twitter has 80 cent eCPMs, vs 71 cents for Facebook:

Twitter’s ability to monetize is improving. It says advertising revenue per timeline view was $0.80 for the three months ending on June 30 of this year, up 26 percent from the same period in 2012. That number is significantly higher in the United States ($2.17) compared to the rest of the world ($0.30), though the international number is up 111 percent year-over-year.

Why invent an entirely new ad metric (and one without a handy acronym)? Well, Twitter has an unusual advertising model, with advertisers paying to promote tweets, trends, and accounts in users’ news feeds, so the standard ad measurement of CPMs (the cost per thousand impressions) may not apply. The fact that “advertising revenue per timeline view” actually measures revenue for every 1,000 timeline views suggests that this metric is may be a proxy of sort for CPMs.

(It’s probably a little dodgy to compare Twitter’s numbers with traditional CPMs, but hey, just for fun — according to eMarketer, Facebook had an effective CPM of $.071 on mobile and $0.19 on desktop in 2012.)

However, Twitter is really selling its ads as a way for companies to engage with consumers, so the filing also notes trends in cost per ad engagement — basically, it’s been falling steadily, with a sequential decrease of 46 percent in the last quarter, 12 percent the quarter before than, and 19 percent the quarter before that. (A decline in cost means Twitter is getting paid less for each engagement.) The filing attributes these declines to an increase in ad inventory, which has been partially offset by growing demand.

Advertising also gets its own section (page 18, if you want to read along) in the filing’s discussion of various risk factors, where Twitter notes that all kinds of things could go wrong with its ad programs — for example if Twitter is unable to convince brands to invest in building a presence on the service, or if new programs like its video-base Amplify ads don’t take off, or if the decline in cost per engagement continues.

As we wrote earlier, Twitter brought in $253 million in revenue in the first six months of the year. Of that amount, $221 million (87 percent) came from ads, compared to $32 million (13 percent) from data licensing. In comparison, the company made $7 million from advertising in all of 2010 (that’s when it launched its first ad programs) and $21 million from data licensing. Oh, and Twitter says that mobile accounts for 65 percent its ad revenue.

Mobile is now a majority of Facebook's ad revenue, too. 

Impressive that Twitter went from 0 to $500 million in revenues in 4 years:

http://allthingsd.com/20131003/how-twitters-ad-business-went-zero-to-500-million-in-less-than-four-years/

Twitter needs to improve its costs:

But the largest portion of Twitter's costs is R&D, which it defines in large part as salaries for engineers. Twitter has 2,000 employees — a massive number for such a simple-looking product. Twitter says, "From January 1, 2010 to June 30, 2013, we increased the size of our workforce by more than 1,800 employees."

Eighteen hundred! For a device that publishes 140 characters at a time. What are they all doing?

More notes on Twitter IPO:

http://pandawhale.com/post/28905/twitters-public-filing-is-out-daily-intelligencer