muyoso, do you have the research from the site to back up those numbers? I'm not about to go digging for it myself...
There are a variety of factors that reduce a lithium ion battery's performance. First of all, lithium batteries have a higher internal resistance than their nickel metal-hydride and nickel cadmium counterparts (counterparts in the sense of their use in cell phones over the years). This is one reason why they heat up quite a bit during both charge and discharge, and consequently "age" faster when existing in a warm environment.
Lithium batteries self-discharge at around 8% per month, and during this time typically suffer a permanent capacity loss when left unused. Batteries that were produced and stored in a warm place for too long will certainly not charge to as high of a capacity as another identical battery that was produced and began earlier discharge cycles in a real-world environment.
Lithium batteries do not have a "memory," which is the effect that nickel cadmium batteries are reputable for carrying over the course of many charge/discharge cycles. In other words, your battery isn't going to suffer because you never let it run dead before charging it all the way back up. It doesn't matter. However, leaving it on a charger with Wi-Fi, Bluetooth, and a high-definition porno on simultaneously will only negatively effect the battery due to the heat generated from current delivery.
Some batteries are simply better than others. This holds true even among batteries of the same brand, capacity and application. The way they are handled, stored and used determines the life and performance of the battery in your phone. In this case, do not drain your battery to 0% before charging it back up. It's typical for lithium batteries' capacity to permanently drop by 15-25% within one year's use.
If you have a spare cell, charge it to about 40%, take it out and put in the refrigerator. Also, make sure you check the manufacturing date on the packaging, as I said before, storing for long periods without a 40% charge or regular charge/discharge cycles will result in a lessened capacity.
Just figured I would throw a few facts out there. I began using lithium batteries for robotics projects a number of years ago when they became much more prevalent.