Comment by noduerme

>> modern SPAs

Right. It's possible now because of things like Puppeteer. That's fairly recent. Nothing like that existed in the early 2000s to allow crawlers to index either Flash, Java embeds, Proce55ing apps or Javascript content. All scripting was a black box to Google as much as it was to Altavista. You had to place ancillary noscript content on each page to make it accessible to robots. That held true for Javascript apps well into the mid-2010s. My point is that we actually could index Flash sites now if we wanted to, just as we do with Javascript SPAs... however no one was making JS SPAs in the early 2000s, and search penalty was one major reason single page Flash sites fell out of use. The fact that JS SPAs have moved in now to occupy the empty niche left by ES4/AS3 really just proves it was a good and necessary idea for certain types of sites that was kneecapped by Adobe's closed source and the direction the web and search was taking.