In US patent 5495566 (filed 1994-11-22, issued 1996-02-27), Microsoft patented varied speed scrolling depending on the speed of mouse wheel spin, something that is now always used. Does this mean that most software that uses scrolling is in violation, or is the technology different?
It means that any software that uses it is possibly in violation. But whether you're actually finally found guilty of being in violation is up to a jury to decide.
You could, however, be sued at any time which means- unless you have very significant legal reserves typically into the millions of dollars- an end to your product and or company.
Virtually every piece of software you might write today could be the legitimate target of a software patent lawsuit. People offer various opinions about this which are intended to be reassuring such as, "it will only happen to you if you're already making a lot of money". That particular meme is something to be wary of, since it's highly misleading. For example, the instance of RunwayFinder vs FlightPrep detailed here:
The bottom line is, this software patent you cite might be used to attack you very effectively if the patent holder so wishes simply by filing a case you must then respond to irrespective of how valid / invalid applicable/ inapplicable the actual patent is ultimately found to be.
Here is a case in which the defendant won, but was still facing numerous other suits from the same litigant and was therefore forced to sell his company to the litigant:
So being found innocent in he eyes of a the law isn't going to save you either.
I say this because when evaluating the danger posed by some patent, it's a mistake to spend much time considering whether or not it applies to you on its technical merits. It actually doesn't matter, unless you have significant legal reserves , a lot of time to fight in court and an appetite for doing so.
If you're worried about a software patent you have a few choices. One is to approach the patent holder and pay what he wants. If you can't / won't do that, you can roll the dice and see if you survive, knowing that you will permanently lose the ability to profit from all your labor should you be served.
Another choice, and this may be the best option, is simply not to sell into markets that permit software patents.
That would at put on the exclude list at least US, AU, and JP and probably others as well. But excluding those markets still leaves a lot of potential customers especially for a small business.
Companies do pursue this strategy for just this reason.
It might be wise to contact a lawyer with respect to developing appropriate advertising sales and licensing approaches as well as articles of incorporation etc. to make sure that execute on this approach correctly.
Or you could try a home grown approach which might consist of incorporating in a non-software patent jurisdiction, refusing all sales which originate from or are to parties within software patent jurisdictions and see how that works for you.
An option you may have overlooked is that patented technology can be licensed, and in fact this is usually the case for commonly used patents.
However, in this case, applications typically will use the platform's own scrolling API (so on Windows they will use Microsoft's own scroll functionality) so there is no conflict.