1. Search engines – Google, Bing, Ask.com and good old Yahoo come to mind. There are also niche-specific (aka vertical) search engines that deal with a specific industry, such as Indeed.com for jobs.
2. Social networks – Facebook, Twitter, LinkedIn, Google+, Pinterest, Instagram, YouTube, Tumblr, Foursquare etc. These sites allow users to create social profiles, add friends, share posts, photos, videos, etc.
3. Forums – Forums are platforms for users who share the same interests (such as marketing, aerospace engineering) to ask questions and share knowledge. Examples in the web & Internet marketing space are Warrior Forum and Black Hat World.
4. Blogs – Blog are mostly personal, or may be managed by a company or a group of enthusiasts. There are blogs on everything: food, fashion, love, finance, skydiving, gaming, motorsports, technology, parenting… that’s because a blog is a ticket for anyone to publish their own opinion in whatever style they like.
5. Portals – Portals are more like gateways to all kinds of information. Think Yahoo, MSN and AOL. They provide news, directories, reviews, stock updates, weather updates, email and everything in between.
6. Corporate – All businesses today need a web presence in the form of a corporate/business website. For example, a creative services agency would need to showcase their portfolio, service description and contact details to harbor any hopes of netting online clients.
7. Ecommerce – ecommerce sites emulate the typical brick and mortar stores with their integration of a shopping cart, product catalog and checkout system. Ebay, Amazon and Godaddy are great examples.
8. File sharing – There are hundreds of file sharing sites out there that allow users to upload their files (photos, documents, videos) and share them with the rest of the world. Users may also opt to password-protect their files. Examples are 4shared, Megaupload, Mediafire, and Slideshare.
9. Informational sites – these sites are built to provide content that solves the informational needs of users. In many instances, a site can double up both as a blog and an informational/news site (e.g. Lifehacker.com). About.com is a great example of a content site that publishes guides on just about any topic you can think of. Most informational sites are niche-specific, with topics ranging from farming to programming.
10. News/media sites – Usually extensions of media companies and news corporations, such as CNN.com, BBC.co.uk, and Reuters.com. ESPN and Goal.com are large news sites in the sports category, while TMZ and MediaTakeOut represent the celebrity gossip space.
11. Crowdsourcing platforms – Sites that provide a web interface for job providers to outsource their projects to freelancers. Elance, Freelancer, Flexjobs and Odesk are popular crowdsourcing sites.