Twitter claimed that an advertiser received 25 times the number of tweets it actually received and it inflated another metric by 680 million until the San Francisco Chronicle double checked the company's figures.

Jeff Elder at the "The Tech Chronicles" on SFGate.com reported: Twitter posts inaccurately high metrics about its ads, changes them after questions

Twitter claimed that 

…the brand Burberry was mentioned in tweets during London Fashion Week 245,762 times. According to Twitter’s blog, this was achieved with the help of Twitter’s advertising products Promoted Tweets and Promoted Accounts.

The real number was just 10,000 tweets.

Twitter also claimed more than 4 billion "potential" impressions for the hash tag #LFW (London Fashion Week) but the real number was about 3.3 billion.

Twitter changed its numbers but did not say anything about the initial claims or apologize for the mistake.

The Twitter ads blog faked tweets by real users to promote its ads platform in a mockup in July. The company later said “We deeply apologize” for the issue, which was also uncovered by SFGate.

As interest rises in Twitter's IPO, its in the company's interest to claim a robust advertising market.