Why Use Robots.txt File ???

"Robots.txt" is a regular text file that through its name, has special meaning to the majority of "honorable" robots on the web. By defining a few rules in this text file, you can instruct robots to not crawl and index certain files, directories within your site, or at all. For example, you may not want Google to crawl the /images directory of your site, as it's both meaningless to you and a waste of your site's bandwidth. "Robots.txt" lets you tell Google just that.
There is a hidden, relentless force that permeates the web and its billions of web pages and files, unbeknownst to the majority of us sentient beings. I'm talking about search engine crawlers and robots here. Every day hundreds of them go out and scour the web, whether it's Google trying to index the entire web, or a spam bot collecting any email address it could find for less than honorable intentions. As site owners, what little control we have over what robots are allowed to do when they visit our sites exist in a magical little file called "robots.txt."
A robots.txt file on a website will function as a request that specified robots ignore specified files or directories in their search. This might be, for example, out of a preference for privacy from search engine results, or the belief that the content of the selected directories might be misleading or irrelevant to the categorization of the site as a whole, or out of a desire that an application only operate on certain data.

The location of robots.txt is very important. It must be in the main directory because otherwise user agents (search engines) will not be able to find it – they do not search the whole site for a file named robots.txt. Instead, they look first in the main directory and if they don't find it there, they simply assume that this site does not have a robots.txt file and therefore they index everything they find along the way. So, if you don't put robots.txt in the right place, do not be surprised that search engines index your whole site.

Pay Per Click Advertising

Pay per click (PPC) is an internet advertising model used on websites, where advertisers pay their host only when their ad is clicked. With search engines, advertisers typically bid on keyword phrases relevant to their target market. Content sites commonly charge a fixed price per click rather than use a bidding system. Pay Per Click is the name given to the online search marketing pricing structure, where advertiser pays the publishing site/engine each time a prospect clicks on his ads. PPC advertising is the placement of a small ad on the search results page for a specific keyword or keywords in return for a specified payment when a visitor actually clicks on the ad. Advertisers pay nothing to appear on the results page per se; they only pay the amount they have agreed to (or bid for) when someone actually clicks on their ad and is taken to the landing page on their website. The term "pay per click" means just what it says: The advertiser pays each time a visitor clicks on the ad.

Pay per click objectives are:
Increase click through rates – decrease click costs – increase conversions
Research your company and market to come up with a list of keyword groups for your products and services. The keyword list will include estimated monthly clicks and costs. You can include proposed ad copy for each of the advertisements.
Make sure your information for the visitors is right and legal such as contact details, your phone no and email id.
Make sure that you are getting individual leads and your competitors are not getting the same leads. Those individuals must be actually interested in your products and services. Carefully analyze your results and check the conversion rate time to time. Update your resources and technical knowledge accordingly, because getting top position is easier than maintaining it. So advance technology is one of the most important ways to generate business leads.