There are hundreds of professional healthcare associations. Pam Pohly's website has a great list: Professional Associations
Major Nursing organizations affiliated with ANA and influence it's policies, see: Organizational Affiliates
My take: by not joining ANY group, nurses are leaving their voice up to other individuals to speak for the profession.
I've been an ANA member since 1982, very active at the district level for 20+yrs. Have attended many ANA national conventions along with PSNA yearly conventions. What I have gained?
A. Political astuteness: learned to work within the politics of workplace, state and national levels.
How to effectively contact local, state and federal legislators influencing legislation within my state and nationally.
Pounded the halls of state capital and Washington legislators office with increased ease.
Prevented PA Board of Medicine introducing healthcare worker assistant under BOM direction.
B. Advocacy and sharing of clinical and professional information.
C. Introduction to and experience with nursing unions and disaffiliation from professional association -many lessons learned, some painful.
D. Networking opportunities: obtained my first home health position from district member who's just opened an new agency.
E. Leadership and running a professional meeting: Learned Roberts Rules or Order
for parliamentary procedure --can follow C-Span government hearings with ease
F. Travel: visited many parts of PA and across US due to conventions and clinical meetings.
G. Learning via Professional publications articles
H. Free and reduced CEU costs.
I. Liability insurance
J. Discounts: auto rental, car insurance
Online Journal of Issues in Nursing Vol 17 2012 No1 Jan 2012 has interesting group of articles regarding Nursing Advocacy.
Overview and Summary: Nurse Advocates: Past, Present, and Future
Kathleen D. Sanford, DBA, RN, CENP, FACHE (January 31, 2012)
Role of Professional Organizations in Advocating for the Nursing Profession
includes Time Line of Developments for the Nursing Profession
Jennifer H. Matthews, PhD, RN, A-CNS, CNE, FAAN (January 31, 2012)