Most reputable job boards have features that enable you to protect your own privacy and confidentiality, control who sees your resume, mask the identity if your current employer (so your employer doesn't know you're looking for a new job), and easily edit and delete your resume or change it from active to inactive.
These privacy and confidentiality issues are more important than ever these days in light of recent revelations of identity theft of resume information.
Many boards also enable you to create multiple profiles for yourself so you can look for various types of jobs. Some permit you to submit a list of your top skills. Resume submission forms generally have questions in addition to a place to submit the actual resume. Some questions are mandatory; others are optional. When a question is optional, consider whether it is to your advantage to answer it. Answering questions about salary or location requirements, for example, may be too limiting.