IZEA.com is a social media marketing company that matches advertisers with bloggers. If you are a writer, blogger, have social media accounts, and are interested in writing for income, IZEA is a great way to make money online.
They sell advertising and web promotion to clients and, once contracted for promotion, they go through their database of social media publishers to find the best match for their clients. They provide sponsored blog posts, sponsored tweets, and sponsored actions through IZEA.com.
SponsoredTweets.com lets clients select individual tweeters, from celebrities to recognised experts. WeReward.com is the sponsored actions site. Clients can select bloggers to promote their products through SocialSpark.com. You can sign up for these programs though the websites above, or go to IZEA.com. You may sign up as a publisher or an advertiser. For additional information on publishing, see this beginner's help page.
As most readers here will be interested in the writing and blogging opportunities, here's how it works:
A client will come to them to buy advertising to promote a specific product or service. The ad will target a specific demographic. IZEA will go through their database and find all bloggers with sites in that specific vertical, and offer them an opportunity to write for the campaign. (Example: If a car manufacturer has a new van designed for families of five or more, IZEA will select bloggers with families of that size or that own that vehicle to blog.)
As a blogger, IZEA will look at your site age, PageRank, traffic (requires Google Analytics), keywords, site reputation, etc. to determine their interest in using your services, and to determine payment (through PayPal). The advertiser also selects the market, so opportunities to write are based on your site's visitors. If you write an article (based on them sending you an opportunity) and post on your site, approval of your content takes 5 to 7 days.
Provided your content passes their review, payment is based on quality of site metrics. I have no exact numbers, but can give you a general idea. A newer site with only a thousand visitors a month (from a specific country) may earn $12 to $15 for a front page article using their client-specified anchor text, whereas a site with ten thousand visitors a month could earn from $50 to $100 for the same article. Get above a hundred thousand monthly uniques in a client selected vertical (where all of the visitors are from the targeted country), and the payment can go into four figures depending on traffic and site quality.
If this interests you, go to SocialSpark.com and sign up. One of the first questions I received when telling someone about this was the new FTC laws that require disclosure of paid promotion. They have an Ethics statement to cover this, and it's a useful guideline for any promotional blog site. The opportunity to make money is currently with North American sites and visitors, but they are growing quickly.