Real estate portal Zillow is rolling out a collaborative tool for buyer agents on Tuesday, with Boston being one of the first markets to have access. The company plans to roll out the product nationwide by the end of the year.

The "Agentfolio" tool allows agents to create unique portfolios for their clients, which allows both parties to set up searches for new listings, select properties for viewing and comment on features they find attractive or undesirable. The idea is to create a one-stop-shop for communications between agent and a particular set of clients, making sure that listings of interest or clients’ evaluations of properties don’t get lost in the flurry of emails and texts that constitute a modern home search.

The tool draws on the full range of Zillow listings and also allows either agent or clients to share links to listings from outside the site. Though Zillow is drawing on MLS data for the markets in which it is operating the tool, behind-the-scenes information like agent comments may not be available through the interface.  The tool is free to Zillow Premier Agents and $25 per month for any agent who does not already advertise on the site.

The product is the result of Zillow’s October 2012 acquisition of Buyfolio, a New York City start-up that created a similar product for that marketplace.

"[Buyfolio] had created a co-shopping platform. In Manhattan, they were already involved in 10 percent of the transactions in that marketplace, which was quite significant," said Cynthia Nowak, a spokeswoman for Zillow.

Zillow also announced a new national advertising campaign Monday, in which two spots, one 30-seconds and one 60-seconds, will run on HGTV, CNN, USA, A&E and Lifetime.