Classified ads are a form of advertising that can help drive traffic to a website and increase sales and search engine rankings. There are many types of online classified advertising including banner ads, sponsorships, text links, video ads, email marketing, and pay-per-click ads. Classified ads are typically brief text-based ads that include a product description and contact information. Popular sites for placing classified ads include Gumtree, Craigslist, Oodle, and OLX. While classified ads provide affordable promotion, they require consistency and placement on multiple sites to achieve good results.