There’s a lot of excitement surrounding Groupon’s decision to sell shares to the public. Morningstar IPO Strategist Bill Buhr says there will definitely be buyers, but he’s concerned about how long the excitement will last.

“We really worry about what happens if that growth doesn’t show up a couple years down the road,” Buhr said. “Maybe they’ve saturated their markets, or people have moved on to the next thing, or there’s just so many online coupon sites that there’s no real customer loyalty or stickiness with respect to the business model.”

Buhr says it’s too early to say for sure, but with the current frenzy around social media companies, Facebook and Twitter could be next to follow suit.

No date’s been set yet for Groupon’s initial public offering, but shares are expected to hit the market in three to four months. A representative from Groupon was unable to comment, citing a Securities and Exchange Commission mandate.

Click here to view Groupon’s S1 filing.