Joining Internet Marketing Associations

I've been apart of this forum for awhile now ,and I've been soaking up all the free information my small brain can handle. I've finally decided to make a real business out of this marketing thing . I was just wondering what are some of your views on joining a Marketing Association , such as SEMPO , IAB , eMarketing Association ,DMA . There are also a few others I've been looking at like Performance Marketing Association and Internet Marketing Association. They all seem like grate organizations to join but I just cant seem to choose one . Any one affiliated with some of these organizations/associations ? Are they even worth joining?