Some games have no public servers provided by the company. If you are playing in a game like that, then starting a team will require you to have an internet connection fast enough to do a host and play, set up a router and have 2 computers, one for you, one for server, or to rent a server. Server rentals run about $100 a month for a T1. If you have a good cable connection, or an upgraded DSL connection, you can host a reasonable number of people. Remember, cable and DSL connesctions have fast downloads, and slower uploads. Hosting a game is limited to the upload speeds, not the download. PC Pit Stop is a good place to check your internet upload and download speed, to see how many people you can host.
If the company provides servers, then forming a team is much easier. You choose a game type to get good at, and then spend some time in the same server, getting good, and building your reputation. The company server becomes your primary team server for playing and recruiting.
If you are playing lots of matches, having a team server creates a home field advantage. Every server plays slightly differently, depending on the speed, location, quality and number of people connected to it. If you routinely play on the same server, you will have a slight advantage over a player who has rarely played on it. The subtle differences in what ping times the server will produce, and how much to lead will help you out. Teams that are designed as match teams, and play multiple matches a week, will always be playing on their team server, or the team server the next match will be on, not on company servers.