Do Americans take MLS seriously?

I know it's meant to be improving and all, but it must be hard to take a league seriously when the clubs have no history and the supporters have very little pion for the sport. It's also tiny compared to the NFL and NBA. Its not really a question of playing standard, I'm sure in many latin american countries where the teams aren't as good as England, Spain and Germany they are still very pionate about it and have rivalries etc. as most of the leagues are very old. Seeing as the MLS is so new, its hard to understand (as a Brit) how you would feel any real connection and loyalty to your team