Online lead generators and aggregators will rake in half of the estimated $1.8 billion that will be spent on online advertising related to real estate this year, with the likes of Realtor.com and IAC/InterActive Corp.'s RealEstate.com typically getting between $8 and $15 per lead, writes MediaPost, citing a new advertising research report issued this week by Borrell Associates.

Search engines account for 27 percent of real estate-related online ad revenues ($506 million), due largely to Google and Yahoo's having "entered this space in a major way," according to the report. Websites of newspapers, local television and radio stations, and home magazines will capture the remaining 23 percent of online real estate ad dollars (around $400 million), predicted Borrell.