Not everyone can afford to buy Microsoft Office and then others don't like anything with Microsoft in the name so they would like to know alternatives. Heck we are using a Mac (not Microsoft Windows).
Truthfully, its difficult to beat the functionality of
Microsoft Excel and Microsoft Powerpoint and Microsoft Word
(proabably in that order)
Some sites to check out for alternatives include:
Apple Numbers, Keynote and Pages its awesome and cheap NeoOffice(cost=free) Papyrus Office Mariner Software Thinkfree