I'm no PPC expert but essentially you pay to have ads put in the sponsored listings located on the search engine results pages. Actually, you only pay when a searcher clicks your ad and arrives at your web sites, theoretically. Now, this is a basic definition but that's about it.
Some time Search engine optimization can take a long time to show results. Pay per click advertising is an effective way to drive traffic to your website. Search engine optimization and article submissions are another form of driving traffic to your website. By the help of PPC marketing you buy search engine traffic based on relevant keywords bought in an auction model.
In general, PPC is a form of CPA - you are paying for a user interaction. You are paying some advertising company (be it Google, Yahoo, MSN, AdBrite, etc..) money each time someone clicks on your ad. The more effective your ad is (in terms of attracting clicks), the more you pay.
You are quite right about PPC. It works on the basis of keywords. When an online seller targets a specific customer base for his product or service and wants to advertise to this particular keywords. And Google, Yhaoo, MSN these are the Search Engine which help traffic based on relevant keywords bought in an actual model
Pay Per Click advertising campaign is keyword selection. Keywords are selected depending on their popularity and relevance to your website. You would have to pay more for the popular keywords and that must be kept in mind while selecting keywords.
PPC advertisement is a form of advertising where advertisers pay for visitors on cost per click basis PPC is well known for getting quick results albeit in the long run possibly more expensive than search engine optimization PPC is only profitable for business since you can start selling your products....