What is a compatible inkjet cartridge 

What is a compatible inkjet cartridge? HP 363 Ink Cartridge

Compatible cartridges are non-OEM new cartridges - not recycled. Compatible printer inkjet cartridges are manufactured by a third party factory to the OEM (Original Equipment Manufacture) specifications. Each printer cartridge is carefully researched, manufactured and tested.

What is a remanufactured cartridge?

A remanufactured ink cartridge is a refilled original cartridge. So as an example they take an empty HP 363 ink cartridge and clean it test it try it and then sell it. Many printer manufacturers now encourage people to recycle ink cartridges and toner cartridges. These recycled cartridges are then refilled or remanufactured. Obviously this idea is also better for your environment.

What does OEM mean?

OEM means 'Original Equipment Manufacturer' which means a cartridge manufactured by the same company as the printer. So if you've bought a Hewlett Packard printer you buy a HP 363 ink cartridge from HP.

Does using remanufactured / compatible inkjet and laser cartridges void my warranty?

According to Hewlett-Packard, the use of a refilled print cartridge does not affect the warranty unless failure or damage is attributable to it. This is typical of all manufacturers' warranties. Keep in mind that the ink does not touch any part of the printer or internal parts other than the cartridge and print head. The ink is applied to the paper as the paper is fed through the printer. So this means we no longer have to buy the genuine HP 363 ink cartridge.

Why should I buy a compatible cartridge?

Why not? The main reason is because it saves you lots of money! What other reason do you need?
Will using a compatible cartridge void my warranty?

Major printer manufacturers sell printers at or below cost. They make their profits from selling the cartridges. Formerly, once you bought your expensive new printer you had no choice but to buy one of their cartridges after yours ran dry. By using compatibles you are cutting into their primary source of profit. Because of this, they will threaten to void your warranty if you use compatible cartridges. They are simply trying to protect their own interests anyway they can. It is however strictly ILLEGAL for them to do so. They CANNOT VOID YOUR WARRANTY simply for using compatible cartridges. There is no reason that you should not use compatible cartridges. They work and will save YOU money.
We've sold hundreds of printer ink cartridges and laser toners and never had an incident where a customer's warranty was "voided" from using our products.

Will I Get the Same Number of Printed Pages From a Compatible Ink Inkjet Cartridge as an Original Cartridge?

You will get at least the same number of printed pages from compatible Inkjet cartridges as you will get from an OEM Inkjet cartridge. Customers are reporting many, many more pages of print per cartridge over their OEM Inkjet cartridges. So hopefully the answers above should go some way to answering your question of What is a compatible inkjet cartridge.