Lotus was one of the major companies that caused the PersonalComputer Revolution. In 1983 they released "Lotus 1-2-3" for the IBM PC, a powerful, easy to use spreadsheet program based on the original spreadsheet VisiCalc.
Lotus 1-2-3 was predicted to make between $1 -> $2 million dollars in it's first year. Pretty reasonable goals really. However, it made $53 million in the first year, and over $100 million sales over and above that the year after. Anyone got any great ideas that they think the computer industry needs? I could do with $250mil in the bank... However, being this successful has problems. They caught the attention of the MicrosoftCorporation Juggernaught. In the 1980s it was rumoured that Microsoft's internal policy was that "DOS isn't done until Lotus doesn't run." if this sounds incredible now, consider at the same time they got caught putting deliberate code in Windows 3.1 that would complain if it ran on the competing DR-DOS operating system.
In 1993 they created Lotus Notes, a program which introduced the concept of "Groupware" to the world.
In 1995, IBM brought Lotus for $3.5 billion dollars.