What do advertisers want their advertisements to achieve?

It totally depends on the what are the client's (advertiser) objectives. Typically its to increase awareness of a product or service. Other objectives include, increase trial usage, increase preference and consideration for a product/service, increase sales, and/or change perception. Typically, though, it is to increase awareness of a product or service. Clients want their advertisements to stand out, to cut through the clutter and to be relevant to consumers who seeking a product/service need.