What is ALA? First remember, it is the world's oldest and largest professional library association. It was founded in 1876 by Justin Windsor, C.A. Cutter, Samuel S. Green, James L. Whitney, Melvil Dui [Melville Dewey], Fred B. Perkins, and Thomas W. Bicknell. As a note of interest, ALA is incorporated in the Commonwealth of Massachusetts. Traditionally the head of the Boston Public Library serves as the agent for service for the Association. For the last several years this has been Bernie Margolis. One of the effects of this is that Massachusetts state law governs some portions of the ALA's activities. This does mean that it is Massachusetts laws which cover official decisions by the association including rules on conference calls and proxy voting. The last time legal counsel (note spelling) advised the association about electronic meetings and voting, Massachusetts state law had not caught up with technology, and it was not permitted (or forbidden).
You can join ALA and belong only to ALA. As a member benefits include the official journal, American Libraries, the ability to vote in elections for association-wide offices (President-Elect, Treasurer, and 100 members of Council), the ability to vote on changes to the Constitution and the Bylaws, and other benefits determined by the Membership office.
Within ALA there are five kinds of units: divisions, round tables, offices, task forces, and committees.