Realtors are professionals who help connect buyers and sellers. Many real estate agents also do rentals, where they connect tenants with landlords and even maintain properties on behalf of landlords. Realtors work by connecting interested parties together and charging a commission for their services. For sales, they only charge a commission to the seller, but for rentals (i.e., agent-managed leases), the commission is charged to both parties involved in the transaction. Realtors usually calculate their fees as a percentage of the sales price (in the case of a sale) and a percentage of the rent (for a lease). The person who wants to sell/rent the property leaves the details of his property with the realtor (in fact, even leaves the keys to the house so that the realtor can arrange a viewing without any hassle). Other interested parties (i.e. buyers/tenants), obtain this information by contacting the realtor. This is how real estate brokers become hubs of information.
Many home seekers (including real estate investors) use the services of a real estate broker not only to get a good deal, but to get a deal quickly. Since real estate brokers are probably most familiar with the market conditions in the area in which they operate, it makes sense to approach them to get an idea of the prices of properties in the area. Realtors will generally know the prices of various properties in the area for different types and locations.
By utilizing the advice provided by a good realtor, a property seller can potentially get a few thousand more for his/her property. A good realtor will also analyze the needs of the homebuyer/tenant and provide advice on what kind of home can be offered to them within their budget. Therefore, a good realtor will not just throw a list of available properties to the buyer/tenant, but will actually discuss their needs and make recommendations. In fact, this benefits the real estate agent in two ways. First, if the Realtor is able to sell the house, they get a commission; and second, if they make the buyer happy as well, they earn a good reputation (and thus more business).
However, it is worth noting that real estate agents work on behalf of sellers. Therefore, be careful if they try too hard to sell a property.