1. PPC Advertising Networks – Google AdSense is the most popular option under this category, but there are also others. Basically you need to sign up with the network and paste some code snippets on your website. The network will then serve contextual ads (either text or images) relevant to your website, and you will earn a certain amount of money for every click.

The profitability of PPC advertising depends on the general traffic levels of the website and, most importantly, on the click-through rate (CTR) and cost per click (CPC). The CTR depends on the design of the website. Ads placed abode the fold or blended with content, for instance, tend to get higher CTRs. The CPC, on the other hand, depends on the nice of the website.

Mortgages, financial products and college education are examples of profitable niches (clicks worth a couple of dollars are not rare), while tech-related topics tend to receive a smaller CPC (sometimes as low as a couple of cents per click).

The source of the traffic can also affect the overall CTR rate. Organic traffic (the one that comes from search engines) tends to perform well because these visitors were already looking for something, and they tend to click on ads more often.

Social media traffic, on the other hand, presents terribly low CTRs because these visitors are tech-savvy and they just ignore ads.

List of popular CPC advertising networks:
» Google Adsense
» Yahoo! Publisher Network (YPN)
» BidVertiser
» Chitika
» Clicksor

2. CPM Advertising Networks – CPM advertising networks behave pretty much as PPC networks, except that you get paid according to the number of impressions (i.e., page views) that the ads displayed on your site will generate. CPM stands for Cost per Mille, and it refers to the cost for 1,000 impressions.

A blog that generates 100,000 page views monthly displaying an advertising banner with a $1 CPM, therefore, will earn $100 monthly.

CPM rates vary with the network, the position of the ad and the format. The better the network, the higher the CPM rate (because they have access to more advertisers). The closer you put the ad to the top of the page, the higher the CPM. The bigger the format (in terms of pixels), the higher the CPM.

You can get as low as $0,10 and as high as $10 per 1,000 impressions (more in some special cases). CPM advertising tends to work well on websites with a high page views per visitor ratio (e.g., online forums, magazines and so on).

List of popular CPM advertising networks:
» Casale Media
» Burst Media
» Value Click
» Advertising.com
» Tribal Fusion
» Right Media

3. Direct Banner Advertising – Selling your own advertising space is one of the most lucrative monetization methods. First and foremost because it enables you to cut out the middleman commissions and to determine your own rates. The most popular banner formats on the web are the 728×90 leaderboard, the 120×600 skyscraper, the 300×250 rectangle and the 125×125 button. The downside of direct banner advertising is that you need to have a big audience to get qualified advertisers, and you will need to spend time managing the sales process, the banners and the payments.

4. Text Link Ads – After Google declared that sites selling text links without the nofollow tag would be penalized, this monetization method became less popular. Many website owners are still using text links to monetize their sites, though, some using the nofollow tag and some not. The advantage of this method is that it is not intrusive. One can sell text links directly through his website or use specialized networks like Text-Link-Ads and Text-Link-Brokers to automate the process.

Text link marketplaces and networks:
» DigitalPoint Link Sales Forum
» Text-Link-Ads
» Text-Link-Brokers
» TNX
» LinkWorth

5. Affiliate Marketing – Affiliate marketing is a very popular practice on the Internet. Under this system you have a merchant that is willing to let other people (the affiliates) sell directly or indirectly its products and services, in exchange for a commission. Sometimes this type of advertising is also called CPA (cost per action) or CPL (cost per lead) based.

Affiliates can send potential customers to the merchant using several tools, from banners to text links and product reviews.

In order to find suitable affiliate programs you can turn to individual companies and publishers like Dreamhost and SEOBook, or join affiliate marketplaces and networks.

List of popular affiliate marketplaces and networks:
» Commission Junction
» ClickBank
» Azoogle Ads
» Link Share

6. Monetization Widgets – The latest trend on the web are widgets that let you monetize your website. Examples include Widgetbucks and SmartLinks. Some of these services operate under a PPC scheme, others behave like text link ads, others yet leverage affiliate links.

Their main differentiator, however, is the fact that they work as web widgets, making it easier for the user to plug and play the service on its website.

List of companies that provide monetization widgets:
» WidgetBucks
» ScratchBack
» SmartLinks

7. Sponsored Reviews – PayPerPost pioneered this model, with much controversy on the beginning (related to the fact that they did not require disclosure on paid posts). Soon other companies followed, most notably Sponsored Reviews and ReviewMe, refining the process and expanding the paid blogging model.

Joining one of these sponsored reviews marketplaces will give you the opportunity to write sponsored posts on a wide range of topics. Not all bloggers are willing to get paid to write about a specific product or website (because it might compromise the editorial credibility), but the ones who do are making good money out of it.

If your blog has a big audience you could also offer sponsored reviews directly, cutting off the commissions of the middleman.

List of sponsored reviews and paid blogging networks:
» PayPerPost
» Sponsored Reviews
» ReviewMe
» BlogVertise
» Smorty

8. RSS Feed Ads – With the quick adoption of the RSS technology by millions of Internet users, website owners are starting to find ways to monetize this new content distribution channel.

Feedburber already has its own publisher network, and you can sign-up to start displaying CPM based advertising on your feed footer. Bidvertiser recently introduced a RSS feed ad option as well, with a PPC scheme.

Finally, some blogs are also opting to sell banners or sponsored messages on their feed directly. John Chow and Marketing Pilgrim are two examples.

9. Marketplaces - Sitepoint is the online marketplace by excellence. Some websites and blogs, however, are trying to replicate that model on a smaller scale. Depending on your niche, a market place that allows your visitors to buy, sell and trade products could work well. Over the time you could start charging a small fee for new product listings.

The problem with this method is that there are no standard software on the web, so you would need to hire a coder to get a marketplace integrated into your website. You can see an example of a marketplaces being used on EasyWordpress and on Mashable.

10. Paid Surveys and Polls – There are services that will pay you money to run a small survey or poll on your website. The most popular one is called Vizu Answers.

Basically you need to sign up with them, and select the kind of polls that you want to run your site. Most of these services operate under a CPM model.

11. Donations – Placing a “Donate” link or button on a website can be an efficient way to earn money, especially if your blog is on a niche where readers learn and gain value from your content. Personal development and productivity blogs, for instance, tend to perform well with donation based systems (one good example being Steve Pavlina).

A small variation of this method appeared sometime ago with the Buy Me a Beer plugin. This WordPress plugin enables you to insert a customized message at the bottom of each article, asking the readers to chip in for a beer or coffee.

12. In-text Adverting – In-text adverting networks like Kontera and Vibrant Media will place sponsored links inside your text. These links come with a double underline to differentiate them from normal links, and once the user rolls the mouse over the link the advertising will pop. Should the user click on it the site owner will make some money.

Some people make good money with this method, but others refrain from using it due to its intrusiveness. It is also interesting to note that very few mainstream websites have experimented with in-text advertising.

13. Pop-ups and Pop-unders – Pop-ups are a common yet annoying form of advertising on the Internet. If you are just trying to make a much money as possible from your website, you could experiment with them.

If you are trying to grow the traffic and generate loyal visitors, however, you probably should stay away from them. Just consider the hundreds of pop-up blockers out there: there is a reason why they are so popular.

Ad networks that use pop-ups:
» Tribal Fusion
» PayPopup
» PopupAd
» Adversal

14. Audio Ads – Also called PPP (Pay Per Play), this advertising method was introduce by Net Audio Ads. the concept is pretty simple: play a small audio advertising (usually 5 seconds) every time a visitor enters into your website. The user should not be able to stop it, creating a 100% conversion rate based on unique visitors.

The company is still rolling tests, but some users are reporting to get from a $4 to a $6 CPM. Regardless of the pay rate, though, this is a very intrusive form of advertising, so think twice before using it.

15. Selling the Website – Selling your website could be your last resource, but it has the potential to generate a big sum of money in a short period of time.

Market places on online forums like DigitalPoint and Sitepoint are always active with website buyers and sellers. Keep in mind that they most used parameter to determine the value of a website is the monthly revenue that it generates, multiplied by a certain number (the multiplier can be anything from 5 to 30, depending on the expectations of the seller, on the quality of the site, on the niche and other factors).

16. Selling an Ebook – Perhaps one of the oldest money making strategies on the web, using a website to promote a related ebook is a very efficient way to generate revenue. You could either structure the website around the book itself, like SEOBook.com, or launch the ebook based on the success of the website, like FreelanceSwitch did we the book How to be a Rockstar Freelancer.

[ Via DailyBlogTips ]