The list of corporations signing on to offer Paypal as a payment option for customers is growing ever longer. Over the last year and a half, airlines such as Northwest and Southwest have jumped on board, allowing customers to use Paypal accounts to pay for flights. Now, the almighty Delta Airlines has followed suit as well.

Paypal offers a truly revolutionary service in that it covers a variety of payment options and is truly completely secure. While it may be easier to hack into a merchant’s system records and uncover scores of customers’ payment details, it is probably a bit trickier to hack into Paypal. Simply because financial transactions make up that company’s sole focus, its security is very likely top-notch and on par with a bank web site.

So customers can now use Paypal as the channel to make purchases on several major airlines with a credit card (including frequent flyer rewards cards), debit cards, bank account transfer or Paypal account funds. And it’s about time. With more than 60 million active accounts in 190 markets and 17 currencies around the globe, it appears Paypal is not going anywhere any time soon. And since it’s here to stay, it’s high time these companies stood up and recognized Paypal for the financial giant that it is. And to think it was once primarily regarded only as a side arm of eBay. That’s so late 90’s.

The world’s first independent credit card company, established in 1950, is changing hands. Owned by Citigroup since 1981, the sell of Diners Club international network and franchisor brand to Discover Financial for $165 million was approved this month. This was cash money, a serious investment that belies how badly Discover wants to expand its payment network around the globe.

According to Banking Times, the sell was designed to “cut costs and increase efficiency,” as Citigroup was pretty banged up by bad debt, including that acquired in the subprime mortgage fallout. Citigroup’s profits for 2007 were down more than 50%, and 2008 isn’t projected to be much better.

According to the article, this acquisition is expected to be a big boost to the ailing Discover Financial:

“Diners Club is accepted at more than 8 million locations in 185 countries and Discover expects the purchase to improve its presence among business travellers, particularly outside the North American market. The transaction should add between $10 million and $15 million to the group’s annual pre-tax profit.”

Other finer points include the fact that Citigroup will retain ownership of 13 Diners licensee territories (roughly 30 percent of the total), including USA, Canada, Europe and Japan. It’s interesting that MasterCard was co-branded on Diners Club cards since 2004, a partnership that is expected to continue in the territories controlled by Citigroup. Discover’s acquisition — which gets it into the commercial market for the first time with more than 80,000 such credit cards — totals $30 billion in charge volume. Everything is expected to be finalized within 60 days.

Your credit score is immensely important, not only in your finances, but in life. Insurance costs, job prospects, and homeownership are all affected by this three-digit number. Determined by the Fair Isaac Corporation, thus the name FICO, your credit score has tremendous power over your life.

This is why it’s quite important to understand what makes up your credit score and how you can control it. As the pie chart shows, your credit score is roughly 35% payment history, 30% amounts owed, 15% length of credit history, 10% new credit and 10% types of credit.

1. Payment History

This is fairly self-explanatory — pay your bills on time, every time. Why? Delinquent payments can stay on your credit report up to seven years. If you have problem paying a bill, talk to the lender and update them on how much you can pay and when it will be available. One important note here is that, while everyday bills like utilities won’t go on your credit report, a late payment on one of these can increase your credit card interest rate (i.e., the monthly amount you must pay). Then, you risk falling behind on the credit card payments and your credit report can become marred.

2. Amounts Owed

This category takes into account not only what you owe currently, but what you could possibly owe in the future if you were to max out all your available lines of credit. Essentially, lenders want to know how much you could borrow from all lenders combined, and whether you would be financially able to pay it all back. This speaks directly to your level of risk as a borrower. One solution is to close lines of credit that are paid off and sitting unused, but only if they are newer accounts from within the last three years or so.

3. Length of Credit History

Lenders like to see an established history of not just having credit cards or loans, but having the same accounts with the same lenders over several years. This is why, if you have lines of credit that are paid off and sitting unused, but have been with you quite a while, you should consider keeping them open. Instead of closing it, ask the lender to reduce the available balance to the minimum, then cut up the card and stop using it.

4. New Credit

Try to limit the amount of new credit accounts you open within a short period of time. Also, try to contain credit inquiries (i.e., credit checks run on you for the purpose of obtaining a loan) within a short time period. If you’re shopping for a car or home loan, lenders are going to be checking your credit report a lot. It is gentler on your credit report to get this all out of the way within a couple weeks, as opposed to a couple months.

5. Types of Credit

Revolving credit, like credit cards, should ideally appear on your credit report alongside installment loans, as in a mortgage or car loan. This shows lenders your level of responsibility in handling a variety of debt.

Also, don’t forget to check your credit report often. The best way to get started is to visit AnnualCreditReport.com. A credit check can help correct any reporting errors, as well as identify weak spots in your report and how they might be strengthened.