Respect, or street cred is an element that was used in Grand Theft Auto: San Andreas to effectively graph how much inclined your gang is to help you. The more respect you have, the more gang members you can recruit to rend to your personal interests. Raising your respect is straight-forward; doing missions and murdering rival gang members and police officers are the most common ways.
Up to seven gang members can be recruited. This will not happen until you have roughly 80% of your respect meter full.