NEW YORK (TheStreet) -- Twitter recently filed its S-1 form with the SEC, as investors anxiously await its IPO. However, TheStreet's Chris Ciaccia and Debra Borchardt provide some warning signs for prospective buyers.The recent success of other social media companies is creating a lot of buzz surrounding Twitter, which plans to use the ticker, "TWTR." While rather high, 83% of its revenues come from advertising. But Ciaccia was quick to point out that it's a similar story with Facebook ( FB), Yelp ( YELP) and other social media companies. He added that it's up to Twitter to convince advertisers to continue using its promoted tweets and posts, which has seemed to work so far, with revenues continuing to more than double year-over-year. Another concern is Twitter's active users, which actually fell, according to the filing. The 218 million monthly active users and 100 million daily users significantly lags behind Facebook. Ciaccia added that 75% of Twitter's revenue comes from the United States, despite its large international presence. That will have to change, as Twitter needs to find a way to tap advertising dollars from other companies abroad. And while Facebook or Google ( GOOG) could come up with a similar platform to Twitter, Ciaccia didn't seem to think that will work. He concluded that Twitter is the place to be for real-time news and breaking stories, which have even moved markets. Although he likes the company's prospects going forward, he admitted that he'd rather buy a mutual fund or business development firm with exposure to the name.