LinkedIn’s 1999-Style IPO Rekindles Questions About Leaving Money On The Table

Please forgive my ignorance. What does "leaving money on the table" / "taking money off the table" actually mean?

EDIT: I guess I get it after reading the article -- leaving money on the table effectively means raising money via the IPO at a valuation less than what is real. Thus they left money on the table that they could have otherwise harvested from the IPO.