The Four Ps of Marketing

The four Ps of marketing is a useful categorization when looking at the marketing mix of a business, and at the marketing decision that a manager can control (subject to certain constraints). The key element of this mix include:
Product aspects: Physical characteristics such as functionality, quality, safety, etc., brand name, design, styling and packaging, as well as warranty, repair and support services.
Pricing: Strategic pricing decision (overall strategy, list price, bundling, etc.), as well as tactical pricing decision (discounting, rebates, terms and conditions, general price flexibility, channel considerations, etc.).
Place / Distribution issues: Overall coverage strategy (selective, broad), general channel decisions, identification of specific distributors or Points of Sale, physical distribution questions (inventory management, warehousing, logistics, etc.).
Promotion decision: Overall promotional strategy (e.g. push vs. pull), advertising, sales force, promotions, PR, etc.

The framework is useful not only in analyzing the marketing mix for a product, but also in understanding the go-to-market strategy for an entire business unit or business.
To framework does have its limitations, though: It seems well suited for physical products, maybe a bit less so for services. And in a world where the traditional marketing tools seem less and less effective, many question the validity of the four Ps. Some have suggested to extend it to a 5th P (e.g. People or Processes). Others have come up with an equivalent four Ps for marketing in the 21st century (see chart). Despite all of that, I still find it a useful concept when looking at a business.