There are currently 20 teams in Major League Soccer. United's closest rivals, in terms of geography will be the Chicago Fire and Sporting Kansas City. Here's a complete list of teams.
The league's web site is at www.mlssoccer.com.
Something different: When you see a team's record in the standings, it will be listed as wins, followed by ties and then losses -- instead of the W-L-T format we're used to from other sports. Here are the current standings.
By the way: If you hear soccer fans talk about "tables," they're talking about league standings. ("Oh, my! Bolton Wanderers have dropped to the bottom of the English Premier League table.")
Who are the stars? Here's a link to the MLS league leaders in an assortment of statistics.
What's a "clean sheet?": It's a shutout. Portland goalkeeper Adam Kwarasey leads MLS with 13 of them.
Soccer wisdom: For a weekly update on an assortment of soccer subjects, you can read the Star Tribune's Soccer Insider column by Jon Marthaler. Northern Pitch is a local soccer blog that writes about the sport at all levels
And finally...: In March, Star Tribune digital sports editor Michael Rand authored a guide to the league as the 2015 season was about to start. It answers all sorts of questions about MLS, from salaries to local connections to a brief history of the league. You can read it here.