Search Engine Optimization
Search Engine Optimization (SEO), considered by many to be a subset of search engine marketing, is a term used to describe a process of improving the volume or quality of traffic to a web site from search engines, usually in "natural" ("organic" or "algorithmic") search results. Those efforts may also be seen in more narrow vertical search engines involving areas such as local search. Many site owners and consultants engaging in SEO attempt to pursue qualified visitors to a site. The quality of visitor traffic can be measured by how often a visitor using a specific keyword phrase leads to a desired conversion action, such as making a purchase, viewing or downloading a certain page, requesting further information, signing up for a newsletter, or taking some other specific action.

Search Engine Optimization is a long, carefully planned and executed method for generating more visits to a website. It involves maximizing your website's structure, content, code, and links. When done properly, various pages within a website bubble up to the top of the search engine results pages (frequently called "SERPs"). Ideally a top 10 placement will be achieved.
Pay-Per-Click Advertising (frequently called "PPC") is a form of marketing that involves paying for each visitor to your site. It typically begins at about 10 cents per visitor but can go up to $10, $20 and more. This gets visitors to a website instantly, not over time as in organic optimization.
The two most popular PPC methods involve placing ads with Google's Adword program and Yahoo's Overture program. In the long run, when Organic Search Engine Optimization is done properly it is much cheaper and can be more effective, although these two approaches can be used together as part of a complete internet marketing plan.

A link from your site to another site and vice versa is called reciprocal link.

Inbound links are nothing more than links coming to a given website from an external website. For example, any links on this website to Google.com are considered to be inbound links to Google.
Over the past 2 years or so, search engines have placed a lot of importance on inbound links. Inbound links are a good way to judge the popularity of a website i.e. the more inbound links a website has, the more important it is considered to be. Many people use words that describe a website in order to link to it, so the words used to the link have become very important. Ideally, all of the inbound links to your website should use your target keywords as the link text.

Link popularity is a measure of how many other sites contain a hyper link to your site. Some search engines, most notably Google, use link popularity as one of their most important criteria in determining page rank. A further component of link popularity is the quality of sites linking to yours. A link to your site from Yahoo! web site will be regarded as more important than a link from your friend's Wedding web site that's hosted on a free server.

PageRank is actually a trademarked term. The trademark belongs to Google Inc. and refers to the "rank" of a website as determined by Google's ranking system. Page Rank is a grade given to a webpage determining the importance in Google's sense. If you have a high rank website, your chances are higher to come on first position as high page rank boost your search result. Page rank is calculated by the inbound link the page is getting.

As with JavaScript, it is too difficult to parse. Some sites use Flash introductions with a skip button. Page with flash intros greatly reduce their rankings and are encouraged to stop using intros. Sites that use Flash for navigation's and interaction etc. are encouraged to use HTML navigation instead and HTML text where possible.

In a word - yes. Every page of a website can be a potential entry point or ‘landing page’ for visitors. You can't predict which page or pages will be ranked the best for specific keywords. As such, each page must be individually optimised too for optimal ranking. Collectively, all pages of your website reinforce the common "theme" of the site, which also can help boost ranking. Don't assume that your home page is the only important page on your site.

The amount of time required to see results of search engine optimization work range anywhere from 2 weeks to a few months. This is dependent on how often search engines update their index and subsequently re-rank sites. The Google Dance for example is almost a spectator sport among the SEO community.

The ideal Consultant is one that understands the dynamics of marketing, business, and technology - and employs the highest levels of integrity in their work. There are a number of unethical practices or shortcuts that can be used in search engine optimization, but the search engines themselves often times will not accept these questionable or "tricky" practices.
You should choose a company that doesn't promote these practices to achieve short-term results for its clients. You should also expect to benefit from the research expertise, customized approached, management expertise, and on-going consultative process from a SEO firm