Should I play Saints Row before Saints Row 2?

Solution 1:

Saints Row 2 does build on from Saints Row 1, but not enough to really ruin the gameplay experience. I had not (and still haven't) played the first one, but I only really got lost as to why my character was in a coma and why Ultor had taken over everything (but the former didn't impact the game, and the latter could just be put down to business decisions).

The only bit that won't make any sense however far you progress through the game (it doesn't take long to understand who Aisha and Gat are) is the bonus mission, where you help out a guy from the first game. However, that is kind of a rubbish mission that is difficult to get to anyway.

Solution 2:

Not necessary if you just get a basic idea of what happened in SR1 on other sources than the game itself. Saints Row wiki, for example. But even that isn't necessary to have fun with the game and understand the most of it. Even if you don't know something, you can easily figure it out yourself, either by deduction or because some major event from the first game is mentioned shortly before/after something supposedly unfamiliar appears before you.