It's good to be a leading group-buying website these days.

LivingSocial raised $400 million in new financing last week, according to New York Times' DealBook. The new round values the country's second largest social coupon website at more than $3 billion.

Just four months ago, (Nasdaq: AMZN) led a smaller round at a presumably much lower valuation. This time around is being joined by T. Rowe Price (Nasdaq: TROW) and new venture capitalists in bankrolling LivingSocial's heady expansion efforts. An IPO can't be too far away.

It's not just LivingSocial closing in on its Wall Street debut with healthy momentum.

I wasn't the only one scoffing at Groupon for rebuffing Google's (Nasdaq: GOOG) seemingly ridiculous $6 billion buyout offer late last year. Boy, was I wrong. These days the IPO chatter and secondary market trades find Groupon being pegged with a whopping $25 billion price tag.

Patience has paid off for Facebook, Twitter, Groupon, and any other dot-com darling that has thumbed its nose at buyout offers that seemed generous at the time but too low in retrospect.

The challenge here is for Groupon and LivingSocial to keep growing. Juicy margins and feeble moats have attracted more than just upstarts. AOL's (NYSE: AOL) and CBS' (NYSE: CBS) have hopped on the bandwagon in recent months. Travel deals publisher Travelzoo (Nasdaq: TZOO) and dining reservations leader OpenTable (Nasdaq: OPEN) have seen their shares skyrocket since embracing the pre-paid voucher model for discounted offers within their respective niches.

Will crowding lead to confusion or a shakeout? Will the viral nature of hot deals backfire when good offers go bad? Will non-discounting merchants find a way to fight back before they lose more business?

Then we have the biggest question of all for prospective investors: Will LivingSocial and Groupon manage to pull off their IPOs before they peak?

Are you looking forward to the inevitable Groupon or LivingSocial IPO? Share your thoughts in the comment box below.