Before I begin, I should probably explain what exactly Mutants and Masterminds is.
The wikipedia page ( http://en.wikipedia.org/wiki/Mutants_%26_Masterminds ) defines it as a pen and paper superhero roleplaying game created by Green Ronin Publishing based on a variant d20 system (of course by Wizards of the coast) that allows characters to create virtually any hero (or villain) conceivable. Currently I believe it's in the third edition. You can find the official website here ( http://www.mutantsandmasterminds.com ), it's definitely worth checking out. I'm not going to attempt to explain exactly how the system works, because I'm absolutely awful at that sort of thing, so if you're curious please check out the website for further information.
I was introduced to Mutants and Masterminds roughly a year ago by a fellow comic enthusiast and writer, and soon after became involved in a campaign. Rest assured, I didn't create this post in order to fawn over my character; I intend to keep references to the game I'm involved in to a necessary minimum.
Anyways, it has become apparent to me, over time, that Mutants and Masterminds has a wide variety of uses and merits to the average comic fan/tabletop gaming enthusiast that go beyond the (rather trite) 'creating existing comic book characters using the M&M system' phase that I believe nearly everyone goes through. Mind you, some people never continue past this phase, even going so far as to use thinly-veiled versions of characters like Wolverine in campaigns, which is rather unfortunate for a variety of reasons.
To the prospective comic writer, Mutants and Masterminds can be a virtually unsurpassed creative tool that can greatly assist in envisioning new characters, plots, etc. Those of you who are familiar with basic Dungeons and Dragons may know what I mean- taking a look through the various Mutants and Masterminds handbooks can really aid in overcoming writer's block or finding new ideas and directions for existing themes, largely because the manuals are full with tips and advice from the creators about using the system to create new and different things for one's campaigns, as is largely the case with most d20 system manuals. For example, in the Core manual there are an assortment of archetype characters included, to be used not only to help newcomers to build functioning characters (which can be hard, as is the case with most pen and paper games) but also to give ideas on how to construct characters with certain abilities and power sets.
How does this aid a writer? Let's say that our writer has created a character with flight, teleportation and invulnerability, but is unsure exactly how those powers work or why the character has them. The core manual, in the section about powers, discusses these problems in brief, and some of the other manuals such as Ultimate Power and Paragons delve further; in fact, I'm not certain but I believe most of the manuals discuss the issue at some length. Or perhaps our writer has an idea for what powers he wants a character to have but has no further ideas about the character. Or he's having trouble coming up with a team of heroes or villains. Or he wants to take his story in a new direction for the next story arc. Again, all of these issues are addressed in the many manuals of Mutants and Masterminds. Helpful manuals span all (three?) editions- for example, I found the Mecha and Manga book very helpful when creating my character, who is based on 3rd edition rules (as long as one gets permission from their GM, rules and mechanics from other editions can usually be employed).
How is this game interesting to a fan? Maybe after reading a comic, you find yourself thinking that a character would be more interesting if they could be written differently, with different powers or a different personality, etc. Mutants and Masterminds allows one to experience that and more. I've found it really changes the way I read comics- I find myself thinking about how characters I read about would fit into the M&M system, and how characters from the campaign I'm in would fit into the world of comics.
It's also a fantastic social tool. I have yet to meet someone who plays Mutants and Masterminds who doesn't read comics in some capacity, and it can be an excellent way to meet new people who have similar interests, kind of like this website.
Anyways, forgive my overwhelming dorkiness. Mutants and Masterminds is something I think anyone who enjoys comics should definately check out.