I hear stories all the time about how so-and-so got into the industry as an actor. Some stories show creativity, others sneakiness, but it all rolls down to a timeline that is pretty statistically accurate.
When the first pictures started showing up on a big screen, there were limited amount of films released by the studios and many of the lead actors were reused in different movies. The main way people got a role in a film at that time was through their connections. Back then the phrase "It's not what you know, it's who you know." was all the hype.
As time moved on, more pictures were being produced and casting directors had their work cut out for them. This was the time when the inquiry letter with an attached headshot was the way to go. That was obviously before the internet, and I don't mean 1995 internet. It seems that the film industry is still quite old-fashioned, so it didn't really catch up to the internet until the mid 2000s, a full ten years after the technology was available.
Once the first emails were exchanged between casting directors and actors, a thing called an EPK was what everyone was raving about. EPKs also known as Electronic Press Kits, were PDF files that contained your headshots, your education, some recent credits and so forth. But soon enough people stopped using those as they were very hard to update, and would become outdated after each and every credit added.
Nowadays, if you want to share your achievements online, you send them to your IMDb page, or your Backstage profile, OR YOUR WEBSITE. That's right, that is what the current EPKs are - your online portfolios. If someone wants to review your work, they can easily do so on your website. These are more powerful than a standard resume, as you can include multiple headhots looks and a video gallery. Websites, when designed well, are easier to update, and they don't have a maximum length like a single page does.
Now, I did say "Your Best" in the title, because I have an agenda, hear me out. :)
Unlike online profiles, websites give you the ability to focus on how you're selling yourself. Whether you want to focus on your acting reels, your headshots or your resume, websites give you an option to put your best foot forward, while online profiles will force you to comply to standards and look identical to other profiles. This might help clarity, but gives zero individuality.
Actor websites will offer the extra SEO value - note that a lot of online profiles will hide your personal information and focus on their own keywords. What this means is that putting keywords like "New Orleans Actress" and "black belt in karate" will get you nowhere on those profiles unless you search within the website. Using google to try to find yourself will work best when the website is dedicated only to you.
There are no distractions on your website (unless your website provider adds distractions). This is my biggest pet peeve with all the weeblies and wixes of the world. Too many website providers put the primary focus on "HEY, THIS IS A FREE WEBSITE, GET YOUR OWN HERE". Not only will online profiles ask visitors to do the same as these nuisance websites, but they will also provide links to other members with whom you might be actually competing.
As a summary, there is no doubt that Actor Websites are the best EPK's now and will remain the preferred way to showcase your work in the future.