By Rami Tzabar
BBC World Service's Digital Planet
Depending on how you see it, Flash is either the whizzy application that brings websites to life with fabulous animations, or the thing that makes websites annoyingly slow to download when all you really want is just to get a bit of information and move on.
Flash has been used to create huge numbers of online games
One of the most successful and pervasive technologies on the web, it started life called Future Splash and became Flash in 1996 when it was bought by Macromedia.
Since then it has become part of the Adobe empire, who claim it is now used by 90% of people on the web.
It has "the fastest take-up rate of any technology on the internet," according to Seb Lee-Delisle, the technical director of Plug-in Media.
"Flash has its own specific purpose on the web - it's all about the entertainment side and creating a really rich user experience that encompasses video, animation and sound," he adds.
"If you want to present that kind of content on the web, then you don't really have that much choice apart from Flash."
Flash celebrated its 10 years at a conference in Brighton in the UK - called Flash On The Beach - which brought together hundreds of developers, designers and illustrators, many of whom work exclusively with the application.
Ten years ago, it was just a way to present animated graphics on a web browser - but people are now experimenting with it in many other ways, for example with mobile phones.
If you look closely, you'll see that only the heads move
However, it remains best known for animation, and not just on the web; increasingly, Flash-based content is broadcast on television.
Dominic Minns of firm Plug-in Media compares it to the revolutionary way that, in the 1960s, animation company Hanna-Barbera came up with the idea of layering cells on top of each other, meaning that much less had to be drawn at any one time.
"Yogi Bear and all those characters have a necktie on, so that they don't have to draw the body again, they can just draw the head and you don't see the join.
"That made animation back then a lot cheaper, and able to be mass-produced for TV."
He adds: "And that's like Flash now - the way that Flash works in that when you animate for Flash, you build up libraries of different animation - someone running, someone talking, all the different mouth shapes.
"Once those libraries are there, you just have to pull them into whatever scene you're producing - you don't have to redraw and redraw stuff, it's all there, making it incredibly cheap to produce, and to a high standard."
However, Flash has a number of critics who point out its chequered history of dealing with security flaws and its increasing use in intrusive online marketing campaigns.
For some web users flash is an annoyance
The result has been a growth in software that blocks Flash applications from running on a computer.
Even at Flash On The Beach there are one or two dissenters, such as New York-based Java and Flash developer Jeff Stearns.
Mr Sterns says he believes that for Flash to be more accepted developers and designers need to be more careful about when and how they use it.
"There's a lot of people who have been abusing Flash in the past," he said.
"They've been using it for everything, and that's not really the way to do it. As with any web technology, you should always use it for what it's best for."