供大于求時關鍵字廣告位拍賣保留價設計研究

摘 要：在關鍵字廣告位拍賣定價中，由于一個關鍵字對應廣告位的數量沒有限制，常出現供大于求的局面，在此背景下本文建立模型并分析了考慮CTR(Click Through Rate)時設置不同保留價對投標者的投標策略與拍賣收益的影響作用。研究發現供大于求時設置保留價對高類型投標者投標激勵效果比較明顯，且較高水平的保留價會導致低類型投標者投標與保留價呈反向變化。當設置保留價水平較低時，拍賣一個廣告位比兩個廣告位收益更高，當設置保留價水平較高時，拍賣兩個廣告位收益大于等于拍賣一個廣告位的收益。研究結論不僅對企業保留價設計提供科學決策依據，也推進了拍賣理論中保留價的設計研究。

關鍵詞：關鍵字廣告位定價;拍賣;保留價

中圖分類號：F224 文獻標識碼：A 文章編號：1003-5192(2011)02-0040-06

Design the Reserve Price for Non-scarce AdWords Auction

ZHANG E1， ZHENG Fei-feng2， LIU Ya-xu3， WANG Ying-luo2

(1.School of Information Management and Engineering， Shanghai University of Finance and Economics， Shanghai， 200433， China; 2.School of Management， Xi’an Jiaotong University， Xi’an 710049， China; 3.School of Economics and Management， Tsinghua University， Beijing 100084， China）

Abstract:Auction is a traditional and efficient mechanism in rare resource allocation， and it is a new strategy for Internet Search Engine providers to price their AdWords as well. However， the number of AdWords places can be infinte related to an AdWords due to Internet technology. As a result， supply often exceeds demand. It is a usual phenomenon that only 1or 2 bidders participate in goole or baidu AdWords auction. This paper will analyze how to design the auction paremeter such as reserve price and ad’s amount in order to maximize the auctioneer’s revenue. We compare double ad auction with unit auction in existing literature under the same reserve price settings. It is shown that the reserve price stimulates high type bidder to bid more aggressively. However， it hinders low type bidder’s bid decreasing till zero as the reserve price increases despite the low reserve price stimulates him to bid higher. Moreover， the auctioneer’s optimal strategy is to auction two ads with higher reserve price or auction one ads when set low reserve price. Our result can help Internet Service Providers make better decision when the demand of adwords is sparse.

Key words:AdWords pricing; auction; reserve price

1 引言

關鍵字廣告位拍賣是近年來搜索引擎提供商發掘出的新盈利模式，有專家稱它是從搜索引擎分出來的金礦［1］。這種拍賣方式最早由美國Overture公司提出并申請了專利，之后，關鍵字廣告位競價發展得非常迅猛。“花5分鐘時間，就可讓您的企業展現在9000萬網民面前；花3毛錢就可以獲得一個真正的潛在客戶。”這是某搜索引擎服務商對其關鍵字廣告位的推廣口號。網絡廣告競價通常采用關鍵字匹配的方式，當查詢者鍵入的關鍵詞與企業發布廣告所選擇關鍵詞匹配時，按照出價高者排名靠前的原則，對同一關鍵詞的中標廣告商進行排名并呈現在查詢者面前。……