Best way to show a client benefits of content marketing and inbound marketing?

I run a web development consultancy that also provides marketing services. How can I convince my clients to let us do content marketing for them?

Most have no idea what content marketing is, so trying to figure out a simple way of explaining to them why it's important.

Keep it simple. Just mention the top benefits of having a content marketing strategy that they'd be interested in:

• Draws in prospects to grow your business
• Prospects are primed for better conversions (since they begin to trust you after reading your content)
• Gives you a recruiting edge
• Opens up communication with potential and existing customers
• Builds reputation and trust in your segment (you become the influencer / thought leader)
• Cheaper compared to other forms of online marketing
• Shows the company's human side
• Improves employee satisfaction by letting them participate

Content marketing is very similar to product placement (link to: Subway's Fresh Artists). It's primary goal from my point of view is to engage users and demonstrate the need for the product, but not the product itself, through useful information. Good content marketing often has strategic product placement, but it's far from a sales pitch and puts the consumer at ease.

These days, this encourages more organic traffic. Users share content when they find it useful, funny or relevant - very seldom do users share advertisements or sales-pitch sites to their social network.

If you're selling cookware, have a vlog about healthy recipes with your product line being used (without harping about it in-vlog); if you're selling a clothing line review fashion for your target demo with available products on the sidebar or such.

For simplicity, there's certainly Wikipedia; which has very little on the subject but does list some great examples.

• 1891: August Oetker sold small packages of his Backin backingpowder to households with recipes printed on the back. In 1911 he started publishing his very successful cookbook. It went through major updates over past 100 years and is one of the most successful cookbooks globally reaching 19 million printed copies. All recipes originated from the test kitchen of the Oetker company and the book was carefully written as a textbook to teach cooking from scratch. Oetker was very aware of the need for good marketing, practical communication and use of his doctor title to lend authority to his marketing.
• 1895: John Deere launched the magazine The Furrow, providing information to farmers on how to become more profitable. The magazine, considered the firstcustom publication, is still in circulation, reaching 1.5 million readers in 40 countries in 12 different languages.[2]
• 1900: Michelin developed the Michelin Guide, offering drivers information on auto maintenance, accommodations, and other travel tips. 35,000 copies were distributed for free in this first edition.[3] Although Michelin eventually began selling these books, the publication still set a precedent for both informative guides and content marketing distribution.[4]
• 1904: Jell-O salesmen went door-to-door, distributing their cookbook for free. Touting the dessert as a versatile food, the company saw its sales rise to over $1 million by 1906.