Seller's agents represent the interests of the seller in a real estate transaction. There are varying degrees by which an agent will serve the seller's needs. Typically they will:
Occasionally, buyers can be assisted in the process of buying by a seller's agent. In these instances, the seller's agent represents the interests of the seller only, and works to get the best price and terms for the seller.
Because commissions are usually paid by the seller, all agents used to be required to represent the seller. This was before the 'buyer's agent' was created. Currently, most buyer's elect to have representation in the form of a buyer's agent or designated agent that can assist them in negotiating a deal.
When seller's agents list homes on the MLS, a "split" is advertised that tells buyer's agents what percentage of sale price will be paid in commission for bringing a buyer. That is how most homes are sold today, with cooperating agents representing each side of the home sale transaction.