Twitter just launched two big, though expected, additions to its advertising program: Promoted Accounts and the integration of ad units with third-party Twitter clients.

Promoted Accounts are the obvious paid counterpart to Twitter’s new “who to follow” [sic] feature. The feature picks out users you might be interested in following algorithmically based on whom you already follow.

Those “suggestions for you – who to follow” are part of the new Twitter advertising model. Pretty effective for brands and companies.

According to sources – sources who despise Mark Zuckerberg and sources who admire him – the only reason The Accidental Billionaires exists is because one of Mark’s Facebook cofounders pitched the book to Mezrich in an attempt to permanently damage Mark’s reputation.

According to those sources, that cofounder and Harvard student is Eduardo Saverin.

This is the story of how Eduardo got so angry at Mark — how, from Eduardo’s perspective, Mark screwed him out of a huge chunk of Facebook stock. It’s also the story of how Mark solved an early problem at Facebook, one that could potentially have prevented the company from becoming the global behemoth it is today.

There is alwys more to the story

Here’s how to summarize the three regimes:

• Jack Dorsey era: Define Twitter as a product — short messaging and publishing — and get the tech-geek set on board.

• Evan Williams era: Scale Twitter as a product and service — turn 20 employees into 300, 1.25 million tweets per day into 90 million per day, get normal people and celebrities and companies using Twitter, etc.

• Dick Costolo era: Scale Twitter as a business — turn a massive communication platform into a massive advertising platform.

The new Twitter platform has been designed to easily accommodate advertising with the much wider right sidebar. It will be interesting to see what happens next.

The new Twitter design is in Preview phase – soon to be switched for all users. I like several of the new features..easy to embed photos, videos; related content; see mini-profiles without leaving your page