More on Twitter's S-1

|By:, SA News Editor

One possible cause for concern for investors: Twitter's (TWTR) "average cost per ad engagement" (i.e. ad prices) has been steadily falling, and dropped 46% Q/Q in Q2. The company attributes this to growing inventory, particularly overseas. However, ad revenue per 1K timeline views rose 26% Y/Y in Q2 to $0.80.

Benedict Evans estimates Twitter is averaging $3/MAU/year in revenue, and seeing 8 timeline views/day per MAU.

International monetization has a ways to go. Q2 ad revenue per 1K timeline views was $2.17 in the U.S., but just $0.30 elsewhere. Facebook can sympathize.

Co-founder Evan Williams owns the largest individual stake (12%). Five VC/investment firms own 5%+ stakes. Unlike Facebook, Google, and LinkedIn, there's no dual-class share structure.