What does the "old school renaissance" (OSR) in role-playing mean to you?

Back in December, Mike Evans asked:

"Many people have different opinions on this... so:

what does the OSR mean to you? What characteristics define it?"

I responded at the time in the thread he started, but wanted to repost my thoughts again here for future reference:

The Old School Renaissance (OSR) in role-playing games seems to mean different things to different people, and I've seen some frustration, especially outside the OSR community with trying to pin down a definition.  Or disdain due to the idea that OSR is simply shorthand for nostalgia-driven, regurgitated pap.

But the ambiguity doesn't really bother me at all.  When I see OSR I know what I'm getting, and nostalgia is only a piece of the formula.

In my mind OSR is associated with any combination of the following:

• Compatibility (either 1-to-1 or in spirit) with older types of games.

• An effort to figure out the mindset which went in to earlier games, approached with both a critical eye and an open mind.  Usually looked at with some understanding of historical context.

• Play styles and mechanics highlighting:

• Player immersion in the character facilitated by having the player-facing mechanics represent things the character would be to some degree aware of.

• Real and interesting choices for payer characters (PCs).

• Awareness that explicitly stating a new PC ability actually imposes a limitation on any PCs lacking such explicit statements.

• Sort of holistic or impressionistic scenario creation through the use of a broad assortment of location details, NPC-triggers and hooks, random tables and periodic checks, etc.  Details which might require both the players and GM to be think dynamically and creatively.  Perhaps what Paolo Greco once referred to as "Bagatelle Accretion". (e.g. dungeon-, hex- or point-crawls)

• The do-it-yourself (DIY) spirit when it comes to creating and modifying game content.

• A willingness to share and borrow ideas freely with minimal jealousy or litigiousness.  Also leading to frequent collaborations.

• Support for new takes on old settings, tropes and material. Or at very least a willingness to live and let live with differing tastes. (The number of disagreements I'd had in other communities with setting-purists had been discouraging.)

• The associated artistic aesthetics and individual artists who share their work so readily. (Support your favorite artists!)