How to rate
The way I see it there are 3 criteria to be used when comparing definitions of progressive philosophy vs. another definition.  Those 3 criteria are encompassing, enticing, and brevity.  These are the criteria I use when looking at another "new" definition of progressivism.  Here's why:

Brevity
It needs to be short enough so that it can work as an elevator pitch or as a sound bite.  It has to be a sound bite so that politicians and activists can use say it and it won't be cut down to leave out important parts by the Corporate Media.  The "Vulcan" philosophy works well here.  "The needs of the many outweigh the needs of the few" can be said in less than 5 seconds at a normal pace.  This works way better than saying, "The needs of a large group of people will sometime be more important than the needs of another group of people that is smaller than the original group of people.  We prefer this not to happen, but when it does the logical choice of choosing the larger group is obvious.  This is not to say that a majority is always more important, but just when it is an either-or situation".  John Kerry wouldn't make a good politician on Vulcan either.

Encompassing
The Progressive philosophy also needs to explain why we support most, if not all, of the positions that we support.  Otherwise, we will just confuse people and they will go back to thinking that we don't believe in anything.  Again, using the "Vulcan" philosophy for example.  It could be used to describe why we support Environmental protection.  "I support reducing air pollution because the needs of everyone to breath clean air is outweighs the needs of corporatists to make lots of money".  However, while it works with environment, it may not always work for other issues, in fact the philosophy could mean the inverse of what progressives believe.  "I support enslaving 49% of the population so that the other 51% can live in luxury".  Or it would simply not make sense, For instance, What does pro-choice have to do with the "Vulcan Philosophy".

Enticing
For obvious reasons the philosophy has to sound good.  It has to be worded in a way that it sounds like anyone in their right-mind would identify with the philosophy.  Conservatives have this.  They say "free market, and family values".  On the surface it sounds like everyone is for that.  "Fiscal responsibility" is something else they used to claim, and, again, who doesn't agree with that.  "Vulcan" Philosophy sounds good on the surface too.  After all, of course the greater good outweighs the needs of the few!

Comparing
With that we can finally do what the title of my article implied, and that is try to find what it means to be a progressive.  It seems that every organization that claims to be progressive has a different definition on their website.  Let's take a look at a few of the larger ones.

The Congressional Progressive Caucus has the progressive promise(their legislative agenda) which is rooted in their 4 core principals:

1. Fighting for economic justice and security for all;
   
2. Protecting and preserving our civil rights and civil liberties; and
   
3. Promoting global peace and security.
   
4. Environmental Protection & Energy Independence
   

This isn't a bad list.  Let's test for brevity first: "I'm a progressive because I believe in economic justice and security for all, protecting and preserving our civil rights and civil liberties, promoting global peace and security, and Environmental Protection & Energy Independence."  This doesn't exactly roll off the tongue, but I think we can fix that.  First of all, number 4 on the list violates my "no issue" rule.  Energy Independence is an issue that comes from philosophy.  We need energy independence for the sake of national security and our economic security.  I would say that Environmental Protection is also an "issue" not a philosophy.  Environmental protection is important for our health and well being which is comes from number 1.  So if We eliminate number 4 and also eliminate some of the verboseness we could get, "I am a progressive because I believe in fighting for economic justice and security, protecting our civil rights and liberties, and promoting our global peace and security." - about 8 seconds, not bad, but 5 seconds is my goal.  I would also say that it is very enticing.  Who doesn't want global peace and security, civil rights, and economic justice?  Well, racists and gay bashers may not like civil rights, corporate execs looking to exploit workers may not like economic justice, and nationalists may not care about global peace and security.

How about the Progressive Democrats of America?  Here's their's vision:

We are specifically committed to the realization of new models for achieving local, national and global security that redirect the current wasteful and obscene levels of military spending toward the uncompromising and effective funding of: health and education programs; an end to discrimination; the provision of full and meaningful employment; and an end to poverty for all people.

Brevity?  Almost 20 seconds to say that.
Enticing? Not to those security moms.  The beginning could immediately put off a lot of people.  Sure they don't mean cutting off ALL military spending and our spending is obscene, but it would take even longer to explain that.
Encompassing?  A few issues I think fall through the cracks.  Immigration reform doesn't fall anywhere here except maybe discrimination?  Maybe it has to do with poverty?  The whole thing is a statement on national security, but you can't say anything like, "I support at least talking to our enemies because of a realization of new models...".

Of all of the organizations that I looked at I think I like the Center for American progress the best.  From the first paragraph of "What we Believe"

As progressives we believe that America should be a country of boundless opportunity--where all people can better themselves through education, hard work, and the freedom to pursue their dreams. We believe this will only be achieved with an open and effective government that champions the common good over narrow self-interest, harnesses the strength of our diversity, and secures the rights and safety of its people.

Brevity:
You may take one look at that and think that that is not brief at all.  I would say that the last sentence covers what progressives believe in all by itself.  "I am a progressive because I believe in an effective government that champions the common good, harnesses the strength of our diversity, and secures the rights and safety of its people."(Note: I cutdown on some of the verbosity)  It takes about 7 seconds to say.  Probably the closest I'll ever get to my goal.

Encompassing:
Try to find a progressive position that doesn't fall within the philosophy.  
Pro-Choice (and secures the rights and safety of its people)
Environment (common good)
Separation of Church and State (harnesses the strength of our diversity)
National Security (secures the rights and safety of its people.)

Enticing
I guess gay-bashers, racists, and pro-theocracy types might not like the diversity thing, but who cares about them?

Let's look at a couple proposals from what I call "Intellectuals".

Paul Waldman has a good write-up in his book. He proposes 5 "pillars of progressivism".  You can read about them in his excerpts Let's test all 5 of them in once sentence:

I am a progressive because I believe in Government that works for Everyone, Opportunity, Security, Individual Freedom, and Progress.

Brevity?  This actually only takes 6 seconds to say.  Only 5 if you rush it which is my goal.
Encompassing?  Waldman designed it that way.  Let me know in the comments if you find a progressive position that doesn't fall within this.
Enticing?  The way it's worded even Racists, CEO's who exploit their workers, and pro-theocracy Fundamentalist Christians would be hard pressed to find anything to not like about it,  Let alone the sane portion of America.
So far he's doing pretty good.  Even better he sums all 5 of the pillars into a quick summation that "Progressives believe 'we're all in it together'".

George Lakoff in his book, "Don't Think of an Elephant" also proposes a definition of the progressive philosophy.  You can read about it at the New Patriot
Like Waldman he too has 5 things that hit on the progressive agenda.  They map almost perfectly to Waldman's (perhaps Waldman was influenced by him since his book was written after Lakoff's).
Waldman \ Lakoff
Security \ Stronger America
Government that works for Everyone \ Effective Government
Individual Freedom \ Mutual Responsibility
Opportunity \ Broad Prosperity
Progress \ Better Future

Since they map so closely I won't analyze Lakoff individually since it's just like Waldman's

Finally, Jeffrey Feldman of the FrameShop  gave us the 3 Ps of Progressive Politics

Principle, Protection, and Participation.

Brevity? How perfect is, "I believe in the 3 Ps of Progressivism: Principle, Protection, and Participation"?  Definitely hits my 5 second goal.
Enticing?  Heck ya.
Encompassing?  This is where I realized this was more of the strategy of the progressive movement rather than the underlying philosophy.  Participation and principle is how the netroots and progressives intend to make our splash on Government and politics, not necessarily how we'll govern once we get there.  Protection is the only thing that relates to governing.

Conclusion
Overall, my preference is for Waldman's definition.  It's encompassing and brief, and I think it's worded better than Lakoff's.  As I find more and more definitions I hope to analyze them against me Brevity, Enticing, and Encompassing(BEE) test.  Please feel free to use the comments to propose your own progressive definition or to critique my 'BEE' test.  I plan on keeping this series going for as long as people show an interest in it.