• by Laurie Sullivan  @lauriesullivan, January 25, 2011

Twitter has begun testing a self-serve ad platform with advertisers and agencies it plans to roll out in the first half of this year, and MediaPost got a glimpse.

Clix Marketing Founder David Szetela began supporting a handful of clients this week. Among them, Guy Kawasaki, who signed on to promote his forthcoming book: Enchantment: The Art of Changing Hearts, Minds, and Actions.

Advertisers participating in the program must commit to three months, Szetela says. "Twitter plans to open up the platform to other beta users in February," he adds.

The self-serve platform lets advertisers create two types of campaigns: Promoted Tweets, which encourage users to engage with the tweet; and Promoted Accounts, which aims to increase the number of followers for an account.

Twitter claims 175 million registered users tweet about 100 million tweets daily. About 30% get created from mobile devices. Twitter.com registers 210 million uniques per month and 115 million page views per day. There are 370,000 new signups daily.

Similar to Facebook, Google AdWords and Microsoft adCenter, Twitter's self-serve platform requires the advertiser to enter a name, and date and time to run the campaign. It also asks for "interests" and "search keywords," as well as a maximum bid and daily budget.

"Interests" refer to words in profiles Twitter members write to describe themselves such as favorite books, music, clubs and industry associations. The interest topics and keywords relevant to the campaign assist in targeting campaigns. In Facebook there are about 16,000 interest categories that advertisers can use to target members, Szetela says.

Although unconfirmed by Twitter, Szetela believes the backend technology crawls tweets and user bios looking for the frequency of repeated words. The platform determines where to insert tweets in the user's timeline, but it's not clear if the algorithm takes into account Twitter followers. Nor is it understood how Twitter will rank the Promoted Tweets in Twitter streams.

It's not clear if Twitter will have quality scores similar to Google. What if tweets or accounts factored in high "engagement rates," which could become equivalent to click-through rates, Szetela says. "It would make sense for Twitter to use engagement rates as a way to rank ads or choose the ones to display," he says. Words entered into the interest and search keyword field when advertiser setup campaigns will match to words entered into the search field on twitter.com. Typing "ipad" into the search box will return Promoted Tweets containing the word "iPad," for example, but it's not clear how many will serve up at once.

To create a Promoted Tweet, the advertiser must choose from among recently tweeted tweets. They appear as content in user timelines, not alongside them, and they are highlighted to users as "Promoted by [Your Account]" Only relevant users see Promoted Tweets -- users who follow accounts similar to the promoted one.

Retweets can be Promoted, but Twitter requires confirmation that the person turning the retweet into a Promoted Tweet has the authority to use it. For example, if AOL Cofounder Steve Case retweeted a tweet by Guy Kawasaki, Case would need to give Kawasaki permission to run the retweet as a Promoted Tweet.

There are several ad payment options: Pay for engagement events (CPE), Pay for impressions (CPM) or Exclusive for daily Promoted Trends. CPE costs the advertiser a minimum of 10 cents each time someone clicks on the link in the tweet, as well as retweets, @replies or favorites for the Promoted Tweet.

Promoted Accounts aim to help companies increase their follower base on Twitter. When there is a relevant recommendation, a Promoted Account will show in the first position down the right rail. Promoted Accounts are suggested to users based on similar Twitter accounts they already follow.

When an advertiser promotes an account, Twitter's algorithm looks at existing accounts that the person follows, as well as keywords targeted to determine when to show an impression. The advertiser is charged when a user chooses to follow the account.

The self-serve platform also integrates analytics tools that allow advertisers to determine return on investment (ROI).