Will Twitter be the last social media site to IPO?

Perhaps the biggest story in digital last week has been Twitter's IPO. And while the social media site may never be mainstream, we can't deny that social content sharing sites such as Twitter, Instagram, Pinterest and of course Facebook will only see more growth in the near future. In fact, two of the most notable "Boom Brands" featured in the recent NY Magazine article were online sites - Tumblr, with over 140 million users, and Airbnb, which boasts Marc Andreeson and Ashton Kutcher as investors. However, according to this Mashable article, Twitter may be the last big social site to IPO for some time. The article states that Twitter is the last of the "Big Four" (Facebook, LinkedIn, Google) and that although newer trendy startups such as Snapchat are increasing in popularity and receiving millions of dollars in VC funding, they won't IPO in the near future for failure to attract the kind of valuation attributable to advertising dollars as larger sites. It will be interesting to see what the next social site to IPO will be, and how long it might take for this next wave of sites to follow the likes of Twitter.