Google Pagerank, Age of the domain and the alexa rank are 3 significant things that u need to take care of while running ur blog. The mixture of all three can make ur blog/site a super success.

Google Pagerank :
Getting a pagerank can be sometimes a long work of patience as google accumulates the details after periodic 6 months of time. So it is better u start off as early as possible after crearting ur blog and work on building links. Link exchanging is the best way to get huge amount of backlinks. You may to pour some bucks out of your pocket to get your blog listed in different directories.
Pagerank come into picture when Selling your domain and Participating in "get paid to post" programs. Pagerank increases the value of your domain, and you can get great deals very quickly for your domain. In "get paid to post" programs, larger number of oppurtunities are available for higher pagerank domains.
Note : your blog URL with nofollow tag will not count for your backlinks. Pagerank has no relation with website traffic.

Age :
As the age of the domin increases its value also increases. It comes into picture when selling your domain.

Alexa Rank :
Alexa rank determines the traffic of your blog. This is important as these stats represent the popularity of your site. Alexa can help you when selling your domain and getting ads or sponsors for your blog.

Hope this helps :)

When going through any money making sites you will constantly come accross these terms. So before getting started it is better to be aware of these terms and what they mean :

CPM-Cost per thousand impressions.
The amount an advertiser pays for one thousand advertisement impressions, regardless of the consumer's subsequent actions.

Impressions - The number of times an advertisement is viewed by web surfers.

PPC-pay per click
Advertising model in which advertisers pay for click-throughs to their website. Ads are served based on keywords or themes.

SEO-search engine optimization
modifying your site for efficient appearance in search engines

PR-page rank
How well a particular web page or web site is listed in a search engine or advertising results.

CTR-click through rate
The percentage of clicks on a link. This is usually a percentage based on the total number of clicks divided by the number of impressions that an advertisement has received.

CPC -> cost per click
The cost or cost-equivalent paid per click-through to an advertiser's website.

CPL -> Cost Per Lead
Advertising expenditure required to obtain each new sales lead

CPS -> Cost Per Sale
Advertising expenditure divided by sales generated to determine the cost to make each sale or the commission payable for each sale generated by an affiliate.

CPA -> Cost Per Action
Cost to an advertiser for each visitor that takes a specific action in response to an ad, such as subscribing to an ezine, requesting a free trial, or making a purchase. Also used to describe advertising employing this model.

CR -> Conversion Rate / Ratio
The percentage of respondents to an ad, or readers of a sales message that complete the action desired

PPA -> Pay-Per-Action
Affiliate commissions where a set amount is paid for generating a specific action, such as taking a free trial or subscribing to an ezine. PPL, PPC and PPS are usually considered as PPA.

PPI -> Pay Per Impression
Where an advertiser pays for each display (impression) of their advertisement (usually a banner)

PPCSE -> Pay Per Click Search Engine
A search engine where the results are composed of advertisers who pay a fee for each click on their listing. Using a bidding system, the advertiser willing to pay the most is ranked highest.

PPS -> Pay-Per-Sale
Where a commission is paid for each sale generated by an affiliate. The commission is usually a percentage of the sale, although sometimes it's a fixed amount.

SEP -> Search Engine Positioning
Getting your page listed on the search engine results page. Similar to SEO.

PTR -> Paid To Read
PTR is the term used for the programs that pay their members to receive their emails.

GPTR -> Get Paid To Read

GPTRE -> Get Paid To Read Email
Above 2 terms are same as PTR.

PTP -> Paid To Promote
Paid to Promote actually means getting paid to send visitors to a site or sign up or refering some product.

PTSU -> ‘Paid To Sign Up’
PTSU could be part of a PTR program. In PTR programs you can often be paid to sign up for other PTR programs.

PP -> PayPal.
This is the payment processor that is most often used in the PTR industry.

EG -> Egold.
Another important payment processor often used in the GPT industry.