The basic difference between the two is the human element. Some-one will review your site and add it to a directory, where as a spider crawls across the web indexing sites automatically to add to a search engine.
When first starting out, don’t get bogged down in reading all you can about search engine optimisation and how to get the number one listing, because you will never get your site finished. Browse a few sites (some are on the Affiliate Resources page) and get a general idea.
That said, make sure you understand how to submit a site to Google. This is the most imortant seach engine at the moment and it pays to do at least a bit of homework. Others worth a mention are Altavista, All The Web and Yahoo! Some of these may charge a fee for submissions whilst others won’t. Some of the costs are unavoidable because you will get traffic from them. The obvious directory is Yahoo and its traffic generating ability can’t be ignored. You will be charged a fee for a business site, with no guarantee of inclusion. They look for unique and useful content and definitely no banner farms. Once again, become familiar with what they like and don’t like.
There are other more focused directories with some aimed at the gambling public. A few of these are listed in the Affiliate Resources page.
A third source of traffic is the hybrid pay per click search engine, commonly known as PPC search engines. As the name suggest, you bid for search terms and your site is displayed according to the amount you bid for the search term. As you can imagine, the popular terms are expensive, so initially, hunt out a few less popular terms and go with those.
As with anything else it is buyer beware. There are far too many out there that don’t generate enough traffic or don’t have accurate statistics. Check out the gambling specific ones are well.
There are also tools available to help you submit multiple bids as well as the popular search terms. Use them wisely and you will get cost effective traffic.