fifty top fashionistas all posted photos of the same lord & taylor dress on instagram at the weekend .
the retailer has admitted that the bloggers got ` unspecified compensation ' to lend their credability and give the dress their seal of approval .
the ploy proved an instant success as the $ 88 paisley asymmetrical dress sold out and created an online buzz for the entire design lab collection .
the deal highlights the gray area of bloggers failing to disclose when they 've received payment for promoting some goods and services .